Waste Bath

What is the best way to disconnect the drains connected to the outside to the bathroom, etc?
I do plumbing and need to disconnect the drain of the tub and sink drain pipe. I have the old model that the stamp instead of setting pipes.So boost they need to renew the lot or can be obtained from old pipes somehow a kind of solution or the brute force and ignorance.
Cut the tube into the joint, then cutting through the joint Longway with a hacksaw careful not to cut the pipe and then use the blade of a screwdriver into the slot to take joint and you should be able to delete it. It's what I did with glued joints when I was plumbing.