[p4] rolling back

[Zoltan Grose]

So I'm 3 changelists deep into a migration effort and things are not  
going well. So I'd like to "undo" the last 3 submitted changes. I've  
never actually gone backward in perforce so some pointers on the  
right way to do it would be great. A quick glance at the  
documentation table of contents didn't show any obvious hits. Is this  
some kind of a forward integration or do I just delete changelists?  
Fortunately (I think), these 3 changelists are the last 3 in the  
database but I'd be interested in the more general case of when they  
might be several changelists back as well.

Thanks in advance. Free beer on me if you're in the Bay Area. =)

-zoltan