How to remove a patch from a port?

[Joshua Tinnin]

I'm wondering how to remove a custom patch for a port. I am sort of new 
at this, but I've managed to learn how to patch a port and upgrade it 
for testing. But I'm not at all sure how to remove that patch if need 
be. What I've been doing is removing a chunk of the ports tree with 
cd /usr/ports && rm -rf */*portname* and then cvsup'ping again, but 
this doesn't seem right or very efficient. I've read the man page for 
patch, but the only thing I can come up with is the reverse option, 
which I must admit I don't totally understand. Can anyone explain this 
in a way that makes sense?

- jt