Benoit,
You would need to update the application to point to the VSM or to the real service, unless you have something in the middle that forwards the request to one of the endpoints. As Kevin mentioned, it would be equivalent as any other web service.
You can also always send the request to the VSM and then change the execution mode from Most Efficient (virtualized response) or Live Invocation (real service response).
Hope it helps.
Heloisa