Merge pull request #223779 from maulikshah23/patch-12

Update automatic-vm-guest-patching.md

Author: prmerger-automator[bot]

articles/virtual-machines/automatic-vm-guest-patching.md

@@ -220,12 +220,20 @@ PUT on `/subscriptions/subscription_id/resourceGroups/myResourceGroup/providers/
 }
 ```
 
-### Azure PowerShell for Windows VMs
-Use the [Set-AzVMOperatingSystem](/powershell/module/az.compute/set-azvmoperatingsystem) cmdlet to enable automatic VM guest patching when creating or updating a VM.
+### Azure PowerShell when creating a Windows VM
+Use the [Set-AzVMOperatingSystem](/powershell/module/az.compute/set-azvmoperatingsystem) cmdlet to enable automatic VM guest patching when creating a VM.
 
 ```azurepowershell-interactive
 Set-AzVMOperatingSystem -VM $VirtualMachine -Windows -ComputerName $ComputerName -Credential $Credential -ProvisionVMAgent -EnableAutoUpdate -PatchMode "AutomaticByPlatform"
 ```
+### Azure PowerShell when updating a Windows VM
+Use the [Set-AzVMOperatingSystem](/powershell/module/az.compute/set-azvmoperatingsystem) and [Update-AzVM](/powershell/module/az.compute/update-azvm) cmdlet to enable automatic VM guest patching on an existing VM.
+
+```azurepowershell-interactive
+Get-AzVM -VM $VirtualMachine -Windows -ComputerName $ComputerName -Credential $Credential
+Set-AzVMOperatingSystem -VM $VirtualMachine -PatchMode "AutomaticByPlatform"
+Update-AzVM -VM $VirtualMachine
+```
 
 ### Azure CLI for Windows VMs
 Use [az vm create](/cli/azure/vm#az-vm-create) to enable automatic VM guest patching when creating a new VM. The following example configures automatic VM guest patching for a VM named *myVM* in the resource group named *myResourceGroup*: