The script does not move VM extensions or any identities assigned to the Virtual Machine. Also, the script will not work for VMs with public IP addresses. Remove these upfront manually.
./move-vm-to-zone.ps1 -SubscriptionName "Michael Mergell - Azure Subscription" -ResourceGroupName "S4H2020" -VirtualMachineName "s4h2020-j2e" -newAvailabilityZoneNumber "1"