diff --git a/shop/app/my-orders/page.tsx b/shop/app/my-orders/page.tsx
index 08739fe..27908d2 100644
--- a/shop/app/my-orders/page.tsx
+++ b/shop/app/my-orders/page.tsx
@@ -132,6 +132,13 @@ export default async function MyOrdersPage() {
                         Details ansehen
                       </Button>
                     </Link>
+                    {o.status === 'pending' && (
+                      <Link href={`/order?id=${o.id}`}>
+                        <Button variant="outline" size="sm" className="border-amber-500/20 hover:bg-amber-500/10 hover:border-amber-500/40 text-amber-400 text-xs">
+                          Bearbeiten
+                        </Button>
+                      </Link>
+                    )}
                     {o.pdf_url && (
                       <>
                         <Button variant="ghost" size="sm" asChild className="text-xs text-slate-400 hover:text-white">
diff --git a/shop/app/order/page.tsx b/shop/app/order/page.tsx
index 4d524a1..da06c87 100644
--- a/shop/app/order/page.tsx
+++ b/shop/app/order/page.tsx
@@ -6,7 +6,12 @@ import { OrderWizard } from '@/components/order-wizard'
 import { redirect } from 'next/navigation'
 import { Suspense } from 'react'
 
-export default async function OrderPage() {
+interface PageProps {
+  searchParams: Promise<{ id?: string }>
+}
+
+export default async function OrderPage({ searchParams }: PageProps) {
+  const params = await searchParams
   return (
     <div className="min-h-screen bg-[#0a0a0a] text-white selection:bg-primary/30">
       <div className="container mx-auto py-10">
@@ -20,19 +25,19 @@ export default async function OrderPage() {
         </div>
         
         <Suspense fallback={<div className="h-96 w-full animate-pulse bg-white/5 rounded-2xl" />}>
-          <OrderDataWrapper />
+          <OrderDataWrapper orderId={params.id} />
         </Suspense>
       </div>
     </div>
   )
 }
 
-async function OrderDataWrapper() {
+async function OrderDataWrapper({ orderId }: { orderId?: string }) {
   const supabase = await createClient()
   const { data: { user } } = await supabase.auth.getUser()
 
   if (!user) {
-    redirect('/auth/login?next=/order')
+    redirect(`/auth/login?next=/order${orderId ? `?id=${orderId}` : ''}`)
   }
 
   // Check user role
@@ -42,6 +47,32 @@ async function OrderDataWrapper() {
     .eq('id', user.id)
     .single()
 
+  let initialOrder = null
+  if (orderId) {
+    const adminClient = createAdminClient()
+    const { data: orderData, error } = await adminClient
+      .from('orders')
+      .select('*')
+      .eq('id', orderId)
+      .single()
+
+    if (error || !orderData) {
+      redirect('/order')
+    }
+
+    const isAdmin = userData?.role === 'admin'
+    const isOwner = orderData.user_id === user.id
+    if (!isAdmin && !isOwner) {
+      redirect('/order')
+    }
+
+    if (orderData.status !== 'pending' && !isAdmin) {
+      redirect('/order')
+    }
+
+    initialOrder = orderData
+  }
+
   const products = await getProducts().catch(() => [])
   const categories = await getCategories().catch(() => [])
   
@@ -75,5 +106,5 @@ async function OrderDataWrapper() {
     console.error('Fehler beim Laden des Profils:', e)
   }
 
-  return <OrderWizard products={products} categories={categories} initialProfile={profile} initialEndCustomers={endCustomers} />
+  return <OrderWizard products={products} categories={categories} initialProfile={profile} initialEndCustomers={endCustomers} initialOrder={initialOrder} />
 }
diff --git a/shop/components/admin/orders-table.tsx b/shop/components/admin/orders-table.tsx
index da4aeb9..4a17953 100644
--- a/shop/components/admin/orders-table.tsx
+++ b/shop/components/admin/orders-table.tsx
@@ -216,22 +216,29 @@ export function OrdersTable({ initialOrders }: OrdersTableProps) {
                       </DropdownMenu>
                     </TableCell>
                     <TableCell className="text-right">
-                      {order.pdf_url ? (
-                        <div className="flex justify-end gap-1.5">
-                          <Button variant="outline" size="sm" asChild className="h-8 border-white/10 hover:bg-primary/20 text-xs">
-                            <a href={order.pdf_url} target="_blank" rel="noopener noreferrer">
-                              <ExternalLink className="w-3.5 h-3.5 mr-1" /> PDF
-                            </a>
-                          </Button>
-                          <Button variant="secondary" size="sm" asChild className="h-8 text-xs">
-                            <a href={`/api/admin/orders/${order.id}/download`}>
-                              <Download className="w-3.5 h-3.5" />
-                            </a>
-                          </Button>
-                        </div>
-                      ) : (
-                        <span className="text-xs text-slate-500 italic">Keine Bestätigung</span>
-                      )}
+                      <div className="flex justify-end gap-1.5">
+                        <Button variant="outline" size="sm" asChild className="h-8 border-amber-500/20 hover:bg-amber-500/10 text-amber-400 text-xs">
+                          <a href={`/order?id=${order.id}`}>
+                            Bearbeiten
+                          </a>
+                        </Button>
+                        {order.pdf_url ? (
+                          <>
+                            <Button variant="outline" size="sm" asChild className="h-8 border-white/10 hover:bg-primary/20 text-xs">
+                              <a href={order.pdf_url} target="_blank" rel="noopener noreferrer">
+                                <ExternalLink className="w-3.5 h-3.5 mr-1" /> PDF
+                              </a>
+                            </Button>
+                            <Button variant="secondary" size="sm" asChild className="h-8 text-xs">
+                              <a href={`/api/admin/orders/${order.id}/download`}>
+                                <Download className="w-3.5 h-3.5" />
+                              </a>
+                            </Button>
+                          </>
+                        ) : (
+                          <span className="text-xs text-slate-500 italic self-center px-2">Keine Bestätigung</span>
+                        )}
+                      </div>
                     </TableCell>
                   </TableRow>
                 );
diff --git a/shop/components/order-wizard.tsx b/shop/components/order-wizard.tsx
index fddbcf6..8d9f8f5 100644
--- a/shop/components/order-wizard.tsx
+++ b/shop/components/order-wizard.tsx
@@ -3,7 +3,7 @@
 import { useState, useMemo } from 'react'
 import { useRouter } from 'next/navigation'
 import { motion, AnimatePresence } from 'framer-motion'
-import { Product, ProductModule, Profile, EndCustomer } from '@/lib/types'
+import { Product, ProductModule, Profile, EndCustomer, Order } from '@/lib/types'
 import { Card, CardContent, CardDescription, CardHeader, CardTitle, CardFooter } from '@/components/ui/card'
 import { Button } from '@/components/ui/button'
 import { Checkbox } from '@/components/ui/checkbox'
@@ -12,7 +12,7 @@ import { Label } from '@/components/ui/label'
 import { Separator } from '@/components/ui/separator'
 import { RadioGroup, RadioGroupItem } from '@/components/ui/radio-group'
 import { Check, ChevronRight, ChevronLeft, ShoppingCart, User, ShieldCheck, Cloud, Utensils, HardDrive, Package, AlertCircle, Loader2, UserPlus, Building2, CreditCard, Calendar, Search } from 'lucide-react'
-import { submitOrder } from '@/lib/actions/orders'
+import { submitOrder, updateOrder } from '@/lib/actions/orders'
 import { createEndCustomer } from '@/lib/actions/end-customers'
 import { Category } from '@/lib/types'
 import { Badge } from '@/components/ui/badge'
@@ -80,11 +80,13 @@ export function OrderWizard({
   categories,
   initialProfile,
   initialEndCustomers,
+  initialOrder,
 }: {
   products: Product[]
   categories: Category[]
   initialProfile: Profile | null
   initialEndCustomers: EndCustomer[]
+  initialOrder?: Order | null
 }) {
   const router = useRouter()
   const [step, setStep] = useState(1)
@@ -96,7 +98,9 @@ export function OrderWizard({
   // Endkunden-State
   const [endCustomers, setEndCustomers] = useState<EndCustomer[]>(initialEndCustomers)
   const [selectedEndCustomerId, setSelectedEndCustomerId] = useState<string | null>(
-    initialEndCustomers.length > 0 ? initialEndCustomers[0].id : null
+    initialOrder
+      ? initialOrder.end_customer_id
+      : (initialEndCustomers.length > 0 ? initialEndCustomers[0].id : null)
   )
   const selectedEndCustomer = endCustomers.find(c => c.id === selectedEndCustomerId) ?? null
 
@@ -134,13 +138,26 @@ export function OrderWizard({
   })
 
   // Abrechnungsmodell-Auswahl ('one_time' = Kauf, 'monthly' = Abo)
-  const [selectedBillingInterval, setSelectedBillingInterval] = useState<'one_time' | 'monthly'>('monthly')
+  const [selectedBillingInterval, setSelectedBillingInterval] = useState<'one_time' | 'monthly'>(
+    initialOrder?.order_data?.billing_cycle ?? 'monthly'
+  )
 
   // Modulmengen (moduleId -> Menge)
-  const [moduleQuantities, setModuleQuantities] = useState<Record<string, number>>({})
+  const [moduleQuantities, setModuleQuantities] = useState<Record<string, number>>(() => {
+    if (!initialOrder) return {}
+    const quantities: Record<string, number> = {}
+    initialOrder.order_data?.items?.forEach(item => {
+      item.selected_modules?.forEach(mod => {
+        quantities[mod.module_id] = mod.quantity ?? 1
+      })
+    })
+    return quantities
+  })
 
   // Datum der letzten Lizenz (Bestandskunden-Update-Logik)
-  const [lastLicenseDate, setLastLicenseDate] = useState<string>("")
+  const [lastLicenseDate, setLastLicenseDate] = useState<string>(
+    initialOrder?.order_data?.last_license_date ?? ""
+  )
 
   const lastLicenseMonths = useMemo(() => {
     if (!lastLicenseDate || customerMode !== 'select' || !selectedEndCustomerId) return null
@@ -174,6 +191,16 @@ export function OrderWizard({
   const [selections, setSelections] = useState<Record<string, CategorySelection>>(() => {
     const init: Record<string, CategorySelection> = {}
     categories.forEach(cat => {
+      if (initialOrder) {
+        const item = initialOrder.order_data?.items?.find(i => i.category_id === cat.id)
+        if (item) {
+          init[cat.id] = {
+            productId: item.product_id,
+            moduleIds: item.selected_modules?.map(m => m.module_id) ?? []
+          }
+          return
+        }
+      }
       const first = products.find(p => p.category_id === cat.id && p.show_in_abo !== false)
       init[cat.id] = { productId: first?.id ?? null, moduleIds: [] }
     })
@@ -335,21 +362,34 @@ export function OrderWizard({
     if (isSubmitting) return  // Doppelklick-Guard
     setIsSubmitting(true)
     try {
-      const order = await submitOrder({
-        selections,
-        moduleQuantities,
-        products,
-        categories,
-        customerProfile: customerData,
-        endCustomerId: selectedEndCustomerId,
-        endCustomer: selectedEndCustomer,
-        billingInterval: selectedBillingInterval,
-        lastLicenseDate: lastLicenseDate || null,
-      })
+      let order
+      if (initialOrder) {
+        order = await updateOrder(initialOrder.id, {
+          selections,
+          moduleQuantities,
+          customerProfile: customerData,
+          endCustomerId: selectedEndCustomerId,
+          endCustomer: selectedEndCustomer,
+          billingInterval: selectedBillingInterval,
+          lastLicenseDate: lastLicenseDate || null,
+        })
+      } else {
+        order = await submitOrder({
+          selections,
+          moduleQuantities,
+          products,
+          categories,
+          customerProfile: customerData,
+          endCustomerId: selectedEndCustomerId,
+          endCustomer: selectedEndCustomer,
+          billingInterval: selectedBillingInterval,
+          lastLicenseDate: lastLicenseDate || null,
+        })
+      }
       router.push(`/order/success?id=${order.id}`)
-    } catch (error) {
+    } catch (error: any) {
       console.error(error)
-      alert('Fehler bei der Bestellung. Bitte versuchen Sie es erneut.')
+      alert(error?.message || (initialOrder ? 'Fehler beim Aktualisieren des Angebots.' : 'Fehler bei der Bestellung. Bitte versuchen Sie es erneut.'))
       setIsSubmitting(false)  // Nur bei Fehler wieder entsperren
     }
   }
@@ -1106,9 +1146,13 @@ export function OrderWizard({
                   disabled={isSubmitting}
                 >
                   {isSubmitting ? (
-                    <><Loader2 className="mr-2 h-5 w-5 animate-spin" /> Bestellung wird verarbeitet...</>
+                    initialOrder ? (
+                      <><Loader2 className="mr-2 h-5 w-5 animate-spin" /> Angebot wird aktualisiert...</>
+                    ) : (
+                      <><Loader2 className="mr-2 h-5 w-5 animate-spin" /> Bestellung wird verarbeitet...</>
+                    )
                   ) : (
-                    'Kostenpflichtig bestellen'
+                    initialOrder ? 'Angebot aktualisieren' : 'Kostenpflichtig bestellen'
                   )}
                 </Button>
                 <Button variant="ghost" className="w-full text-white" onClick={prevStep}>
diff --git a/shop/lib/actions/orders.ts b/shop/lib/actions/orders.ts
index 988b3d1..189ba7f 100644
--- a/shop/lib/actions/orders.ts
+++ b/shop/lib/actions/orders.ts
@@ -374,3 +374,231 @@ export async function updateOrderStatus(
   revalidatePath('/my-orders')
   return updatedOrder as Order
 }
+
+export async function updateOrder(
+  orderId: string,
+  params: {
+    selections: WizardSelections
+    moduleQuantities?: Record<string, number>
+    customerProfile: Partial<Profile>
+    endCustomerId?: string | null
+    endCustomer?: EndCustomer | null
+    billingInterval?: 'one_time' | 'monthly'
+    lastLicenseDate?: string | null
+  }
+): Promise<Order> {
+  const { selections, moduleQuantities, customerProfile, endCustomerId, endCustomer, billingInterval, lastLicenseDate } = params
+  const supabase = await createClient()
+  const admin = createAdminClient()
+
+  const { data: { user } } = await supabase.auth.getUser()
+  if (!user) throw new Error('Not authenticated')
+
+  // 1. Fetch current order & verify permissions
+  const { data: existingOrder, error: fetchError } = await admin
+    .from('orders')
+    .select('*')
+    .eq('id', orderId)
+    .single()
+
+  if (fetchError || !existingOrder) {
+    throw new Error(`Bestellung nicht gefunden: ${fetchError?.message || 'Unbekannt'}`)
+  }
+
+  const { data: dbUser } = await admin
+    .from('users')
+    .select('role')
+    .eq('id', user.id)
+    .single()
+
+  const isAdmin = dbUser?.role === 'admin'
+  const isOwner = existingOrder.user_id === user.id
+
+  if (!isAdmin && !isOwner) {
+    throw new Error('Keine Berechtigung dieses Angebot zu bearbeiten.')
+  }
+
+  if (existingOrder.status !== 'pending' && !isAdmin) {
+    throw new Error('Nur Angebote im Status "Eingegangen" können bearbeitet werden.')
+  }
+
+  // Fetch catalog directly from DB to prevent client tampering
+  const dbProducts = await getProducts()
+  const dbCategories = await getCategories()
+
+  // ─── Constraint Validation ──────────────────────────────────────────────────
+  for (const cat of dbCategories) {
+    const sel = selections[cat.id]
+    if (cat.is_required && (!sel || !sel.productId)) {
+      throw new Error(`Die Kategorie "${cat.name}" ist ein Pflichtfeld, wurde aber nicht ausgewählt.`)
+    }
+    if (sel?.productId) {
+      const prod = dbProducts.find(p => p.id === sel.productId)
+      if (!prod) {
+        throw new Error(`Das ausgewählte Produkt für Kategorie "${cat.name}" wurde nicht gefunden.`)
+      }
+
+      // Validate selected modules
+      for (const mId of sel.moduleIds) {
+        const mod = prod.modules?.find(m => m.id === mId)
+        if (!mod) {
+          throw new Error(`Das Modul mit ID "${mId}" gehört nicht zum Produkt "${prod.name}".`)
+        }
+        // Requirements check
+        if (mod.requirements && mod.requirements.length > 0) {
+          const missing = mod.requirements.filter(reqId => !sel.moduleIds.includes(reqId))
+          if (missing.length > 0) {
+            throw new Error(`Das Modul "${mod.name}" setzt die Aktivierung anderer Module voraus.`)
+          }
+        }
+        // Exclusions check
+        if (mod.exclusions && mod.exclusions.length > 0) {
+          const conflicting = mod.exclusions.filter(exId => sel.moduleIds.includes(exId))
+          if (conflicting.length > 0) {
+            throw new Error(`Das Modul "${mod.name}" schließt die Kombination mit anderen gewählten Modulen aus.`)
+          }
+        }
+      }
+    }
+  }
+
+  // Product-level constraints validation
+  const selectedProductIds = Object.values(selections)
+    .map(s => s.productId)
+    .filter((id): id is string => !!id)
+
+  for (const prodId of selectedProductIds) {
+    const prod = dbProducts.find(p => p.id === prodId)
+    if (!prod) continue
+
+    // Product requirements check
+    if (prod.requirements && prod.requirements.length > 0) {
+      const missing = prod.requirements.filter(reqId => !selectedProductIds.includes(reqId))
+      if (missing.length > 0) {
+        const missingNames = missing
+          .map(reqId => dbProducts.find(p => p.id === reqId)?.name || reqId)
+          .join(', ')
+        throw new Error(`Das Produkt "${prod.name}" erfordert die Auswahl von: ${missingNames}.`)
+      }
+    }
+
+    // Product exclusions check
+    if (prod.exclusions && prod.exclusions.length > 0) {
+      const conflicting = prod.exclusions.filter(exId => selectedProductIds.includes(exId))
+      if (conflicting.length > 0) {
+        const conflictingNames = conflicting
+          .map(exId => dbProducts.find(p => p.id === exId)?.name || exId)
+          .join(', ')
+        throw new Error(`Das Produkt "${prod.name}" schließt die gleichzeitige Auswahl von folgenden Produkten aus: ${conflictingNames}.`)
+      }
+    }
+  }
+
+  // 1. Snapshots aufbauen
+  const customerSnapshot = buildCustomerSnapshot(customerProfile, endCustomer ?? null)
+  const orderSnapshot = buildOrderSnapshot(selections, dbProducts, dbCategories, billingInterval, moduleQuantities, lastLicenseDate)
+  const orderHash = hashOrderSnapshot(orderSnapshot)
+
+  // 2. Bestellung in DB aktualisieren
+  const { data: order, error: orderError } = await admin
+    .from('orders')
+    .update({
+      end_customer_id: endCustomerId ?? null,
+      total_price: orderSnapshot.total,
+      customer_data: customerSnapshot,
+      order_data: orderSnapshot,
+      order_hash: orderHash,
+    })
+    .eq('id', orderId)
+    .select()
+    .single()
+
+  if (orderError || !order) throw orderError || new Error('Fehler beim Aktualisieren der Bestellung.')
+
+  // 3. PDF generieren und überschreiben
+  try {
+    const buffer = await renderToBuffer(
+      React.createElement(InvoicePDF, {
+        order,
+        customer: customerSnapshot,
+        orderSnapshot,
+      })
+    )
+
+    // PDF hochladen (upsert: true, um das alte zu ersetzen)
+    const fileName = `ab_${order.id}.pdf`
+    const { error: uploadError } = await supabase
+      .storage
+      .from('invoices')
+      .upload(fileName, buffer, { contentType: 'application/pdf', upsert: true })
+
+    if (uploadError) {
+      console.error('PDF Upload Error:', uploadError)
+    } else {
+      const { data: publicUrlData } = supabase.storage.from('invoices').getPublicUrl(fileName)
+      await admin.from('orders').update({ pdf_url: publicUrlData.publicUrl }).eq('id', order.id)
+      order.pdf_url = publicUrlData.publicUrl
+    }
+
+    // 4. E-Mail mit PDF-Anhang an den Besteller senden (Info über Änderung)
+    const orderUserEmail = user.email || (await admin.auth.admin.getUserById(existingOrder.user_id).then(res => res.data.user?.email))
+    if (orderUserEmail) {
+      try {
+        const formattedDate = new Date(order.created_at).toLocaleDateString('de-DE')
+        const formattedTotal = order.total_price.toLocaleString('de-DE', { style: 'currency', currency: 'EUR' })
+
+        await sendMail({
+          to: orderUserEmail,
+          subject: `Angebotsänderung ${order.order_number}`,
+          text: `Hallo,\n\nihr Angebot wurde erfolgreich aktualisiert!\n\nNeue Angebotsdetails:\n- Anfrage-Nummer: ${order.order_number}\n- Datum: ${formattedDate}\n- Endkunde: ${customerSnapshot.company_name}\n- Gesamtsumme: ${formattedTotal}\n\nIm Anhang dieser E-Mail finden Sie Ihr aktualisiertes Angebot als PDF-Dokument.\n\nViele Grüße,\nIhr CASPOS Shop-Team`,
+          html: `
+            <div style="font-family: sans-serif; max-width: 600px; margin: 0 auto; padding: 20px; border: 1px solid #e2e8f0; border-radius: 8px;">
+              <h2 style="color: #0f172a; margin-bottom: 16px;">Ihr Angebot wurde aktualisiert!</h2>
+              <p style="color: #475569; font-size: 16px; line-height: 1.5;">Hallo,</p>
+              <p style="color: #475569; font-size: 16px; line-height: 1.5;">Ihr Angebot mit der Nummer ${order.order_number} wurde erfolgreich aktualisiert.</p>
+              <div style="background-color: #f8fafc; border: 1px solid #e2e8f0; border-radius: 6px; padding: 16px; margin: 24px 0;">
+                <h3 style="color: #0f172a; margin-top: 0; margin-bottom: 12px;">Neue Anfrage-Details</h3>
+                <table style="width: 100%; border-collapse: collapse; font-size: 14px; color: #475569;">
+                  <tr>
+                    <td style="padding: 4px 0; font-weight: bold; width: 140px;">Anfrage-Nummer:</td>
+                    <td style="padding: 4px 0;">${order.order_number}</td>
+                  </tr>
+                  <tr>
+                    <td style="padding: 4px 0; font-weight: bold;">Datum:</td>
+                    <td style="padding: 4px 0;">${formattedDate}</td>
+                  </tr>
+                  <tr>
+                    <td style="padding: 4px 0; font-weight: bold;">Endkunde:</td>
+                    <td style="padding: 4px 0;">${customerSnapshot.company_name}</td>
+                  </tr>
+                  <tr>
+                    <td style="padding: 4px 0; font-weight: bold;">Gesamtsumme:</td>
+                    <td style="padding: 4px 0; font-weight: bold; color: #0f172a;">${formattedTotal}</td>
+                  </tr>
+                </table>
+              </div>
+              <p style="color: #475569; font-size: 16px; line-height: 1.5;">Im Anhang dieser E-Mail finden Sie Ihre aktualisierte Anfragebestätigung als PDF-Dokument.</p>
+              <p style="color: #475569; font-size: 16px; line-height: 1.5; margin-top: 24px;">Mit freundlichen Grüßen,<br>Ihr CASPOS Shop-Team</p>
+            </div>
+          `,
+          attachments: [
+            {
+              filename: `Angebotsbestaetigung_${order.order_number}.pdf`,
+              content: buffer,
+              contentType: 'application/pdf',
+            }
+          ]
+        })
+      } catch (mailError) {
+        console.error('Failed to send order update confirmation mail:', mailError)
+      }
+    }
+  } catch (pdfError) {
+    console.error('PDF Re-generation Error:', pdfError)
+  }
+
+  revalidatePath('/my-customers')
+  revalidatePath('/my-orders')
+  revalidatePath('/admin/orders')
+  return order as Order
+}