You can de-register an SMA 500v for Azure directly from the Secure Mobile Access interface. Removing the registration puts the virtual appliance into an unregistered state and deletes the binding between it and its serial number in MySonicWall. At that point, you can use that serial number to register the same or another SMA 500v for Azure instance. Only one SMA 500v for Azure instance is allowed per serial number.
To De-register an SMA 500v for Azure
Under Settings Management, click Export Settings to export a copy of your current configuration settings before de-registering your SMA 500v for Azure. This makes it possible to import these settings to another SMA 500v for Azure instance.
Be sure to export your configuration settings before de-registering your SMA 500v for Azure. You cannot recover them after de-registration.