I apologize for my utter lack of Soundbooth and basic sound editing, but I'm curious if the following is even possible.
On a recent shoot, my A camera was setup with two separate lav mics going to discrete L/R channels. Mic 1 was on the left, Mic 2 on the right. Of course, each actor bleeds onto the other's channel slightly and my question is this: Is there a way to remove or cancel one channel out of the other?
I believe that this is what the ADR (Automated Dialogue Replacement) phase of a project is for. Not to remove crossed dialogue from the track (which, to my knowledge, can't be done without hurting the major voice in the track), but to replace the original with a higher quality studio recording of the voice. Check out this link:
That said, if all you're getting is the second actor in areas where the other actor isn't speaking, it's simple: select the section where the second actor speaks, and use the "insert silence" function (I think it's CTRL-T).
Creative Director / Multimedia Specialist
B&S Exhibits and Multimedia