Quite possible, and relatively easy to do.

Just keep this guide handy:

http://msdn.microsoft.com/en-us/library/ms143799(v=sql.105).aspx

and you shouldn't have any problems.

Of course, you also need to change the connection on the workstations, which depends on the app how you do that.

With just four workstations, that shouldn't be too bad...

Jason