I'm in the process of removing a stand alone shower that is in my basement. I want to replace the fixtures that are leaking. It appears that I will have to remove the drain ring, and gasket from the PVC drain pipe before I can move the shower stall and have access to the pipes behind the stall. My question is, how to remove the drain cap and gasket?? Do they unscrew or do I have to pry them off with the chance of destroying the PVC drain. Any help would be greatly appreciated!!

Thanks!!