Sir, I have a leak with in my walls dealing with the tub overflow gasket and th bottom gasket on the tub drain, these are old gaskets seem to be made of soft rubber, have been on tub and in house for over 18 years.. how do I get the p.v.c. connections off at both locations and replace the gaskets? Murphy's Law usually comes into play with me, so I am trying to anticipate the worse scenario... thank you in advance, I am quite a novice and go back to work on the North Slope this Thursday, I need to get this repaired for my wife.. a.s.a.p... at least we do have a second shower should anything go awry.

Semper-Fi :D
John in Alaska

You don't generally take apart PVC cemented joints. You cut and start over unless someone provided a union, Rubber Fernco or No Hub hose clamp kind of clamp coupling.

The "shoe", which is the tub drain should unscrew. Worst case, it has to be cut off carefully.