Replacing shower drain gasket

I have a 2010 30' Classic Limited that the shower drain gasket has begun to come out. When I cleaned the drain because of slow draining, I found the gasket was blocking part of the drain catching hair. According to AS tech, I must remove the bedroom wall on the shower side to get to the nut holding the drain in place. Does anyone know how to remove the carpeted panel on the outside wall? Thanks in advance for any help.