If he's running v7, it's a bit different. I don't have a v7 instance going ATM, so I can't exactly explain the procedure.
I'm not sure I understand the problem for that matter. If stuck on an work server such that you get an assignment from the same project, with different (R,C,G), adding or deleting the advanced client-type in v7 or the -advmethods flag in v6 will change work servers. If you're getting the same P(R,C,G) over and over, its completely different and likely caused by not returning results, invoking lost WU protocol from the AS.