Added sub-section for vnet integration

added sub section for "Check whether the virtual network was used by a web app for VNet integration" and pointing to the newly added troubleshooting steps in the VNet Integration page - https://docs.microsoft.com/en-us/azure/app-service/overview-vnet-integration#deleting-the-app-service-plan-or-web-app-before-disconnecting-the-vnet-integration.

Author: laghim

articles/virtual-network/virtual-network-troubleshoot-cannot-delete-vnet.md

@@ -15,6 +15,7 @@ ms.tgt_pltfrm: na
 ms.workload: infrastructure-services
 ms.date: 10/31/2018
 ms.author: genli
+ms.custom: fasttrack-edit
 
 ---
 
@@ -33,6 +34,7 @@ You might receive errors when you try to delete a virtual network in Microsoft A
 5. [Check whether the virtual network is connected to other resource](#check-whether-the-virtual-network-is-connected-to-other-resource).
 6. [Check whether a virtual machine is still running in the virtual network](#check-whether-a-virtual-machine-is-still-running-in-the-virtual-network).
 7. [Check whether the virtual network is stuck in migration](#check-whether-the-virtual-network-is-stuck-in-migration).
+8. [Check whether the virtual network was used by a web app for VNet integration](#check-whether-the-virtual-network-was-used-by-a-web-app-for-vnet-integration).
 
 ## Troubleshooting steps
 
@@ -103,7 +105,11 @@ If the virtual network is stuck in a migration state, it cannot be deleted. Run
 Move-AzureVirtualNetwork -VirtualNetworkName "Name" -Abort
 ```
 
+### Check whether the virtual network was used by a web app for VNet integration
+
+If the virtual network was integrated with a web app in the past, then the web app was deleted without disconnecting the VNet integration, see [Deleting the App Service plan or web app before disconnecting the VNet integration](https://docs.microsoft.com/en-us/azure/app-service/overview-vnet-integration#deleting-the-app-service-plan-or-web-app-before-disconnecting-the-vnet-integration).
+
 ## Next steps
 
 - [Azure Virtual Network](virtual-networks-overview.md)
-- [Azure Virtual Network frequently asked questions (FAQ)](virtual-networks-faq.md)
+- [Azure Virtual Network frequently asked questions (FAQ)](virtual-networks-faq.md)