I have a PVC drain that I need to change because of the new lavatory sink base that is going in. Is seems that many of the 90 degree joints are "glued in" place. Thus, I cannot simply turn the joint into the config that I need. Is there some type of solvent to get those joints to release? Or do I need to cut them off. And if I do that, how will I re-attach? I suspect that one pipe was fitted into the next, before it was glued.