NLB, resetting affinity

I have NLB with single affinity applied to two servers.

Now we've got a problem which occurs only on web1, and not on web2. My
work 
pc is bounded with single affinity to web2, so to make the tests I always 
have to go walking around in my company trying to find a free pc bounded
to 
web1.

Is there a way to reset the affinity for a single client? Or to reset the 
affinity status on the cluster without shutting down the whole thing.

Fabrizio Cipriani