If you are talking about very small drifts out of synch you could try making small selections and using the Effects > Change Tempo to stretch/shrink that selection. This effect does not change the pitch of the music. I use it to alter the duration of an entire piece of music but it works on any selected audio.
An alternative approach, possibly worked in tandem with the other one would be: select the part you want to move and split it off onto a separate track then use the timeshift tool to reposition that part. If you are always bringing things forward along the timeline a small fade-in/fade-out pair would probably hide the join. If you’re going the other way along the timeline, you’ll probably need to “stretch” one or other of the two part-tracks to close up the gap.
As this is a technique I haven’t tried for this specific purpose, but might want to at some future date, I’d appreciate some feedback as to how you get on. Good luck!