I am replacing a tiled shower floor with a custom fit shower pan. The drain hole alignment is not an issue as it is "custom" placed. However, to install it and the drain that comes with it, requires that the PVC pipe be 1/4" above the new pan hole. Currently the drain is flush with the concrete floor and the pipe is below the concrete floor level. Do I chip around the drain and remove it (cut it out if necessary) then add an extension to the pvc pipe to get the 1/4" clearance of pipe I need above the new shower pan hole? If so, how do I do this? Or, are there any better ideas?

Currently the drain is flush with the concrete floor and the pipe is below the concrete floor level. Do I chip around the drain and remove it (cut it out if necessary) then add an extension to the pvc pipe to get the 1/4" clearance of pipe I need above the new shower pan hole? If so, how do I do this?
I assume that you've already removed the shower pan and flange type drain and all you have is the trap raiser flush with the floor.
You're going to hafta open up a area around the pipe and cut it back with a inside PVC cutter,(see image) far enough to prime and glue a 2" PVC Coupling on to the pipe. You nay now measure to get the 1/4" clearance of pipe you need above the new shower pan hole and then prime and glue in a extension pipe. You mkay now parch the opening you chipped out. Good luck, Tom

Tom, thanks so much, that answers my question. Just one more question: When you say "prime", what does that mean? Is it just making sure the pipe surface is clean so that the glue will adhere to it? Is the glue basically pvc cement?

When you say "prime", what does that mean?
When you glue (or cement PVC you must use primer before you glue. Other uou won't get a good joint. Cheers, Tom