I need some help. I am re-tiling my shower stall on second floor and need to know how to remove the existing vinyl/plastic shower pan & replace the old plastic PVC drain pipe/fitting and replace with a new drain for new membrane shower pan & tile ? I don't want to cut a hole in my kitchen ceiling

You shouldn't have to open up the ceiling to replace the drain and pan.
The drain is a flange type shower drain,(see image) and unless its cruddy I'd reuse it and save the hassle of cutting it out. If you want a new drain then purchase a new flange type shower drain and keep the bottom part and replace the top part. Remove the tile and mortar, remove and save the bolts from the shower flange and pull the drain assembly up and out. The shower pan may be nailed to the studs but you should be able to lift it right out. If it gives you any trouble simply cut that sucker out. Stuff rags in the hole4 and when you go to tile do not let mortar get in the weep holes in the bottom flange. More questions? I'm as close as a click. Good luck and thank you for rating my answer. Tom

Tom "speed ball" Thank you for your prompt response, the image in your reply/advice does not seem to match the drain my shower base pan.. I do have a stainless strainer which is just flat piece of stainless without any bottom pipe attachment, my drain strainer just seems to lay/sit in place in an indent my vinyl shower pan. The strainer is easily removed with just my finger nail tip... when I remove it and look into the drain. I see Black PVC drain pipe through the hole.. and this seems to seems to be connected to the black flared PVC pipe leaving my shower pan, the black PVC collar appears to be pressed into or glued inside to the PVC drain pipe that runs under the sub floor underneath the shower pan.. so unfortunately it does not look like it unscrews.. I would appreciate any more advice you might have