from sweat to sharkbite

Is it possible to reuse the end of a previously soldered pipe in a sharkbite fitting? I need to remove a sweated elbow but not lose length of the pipe. A 3/4" sharkbite needs an 1" of pipe to engage in the fitting correct? Would a 3/4 sharkbite elbow and 3/4 copper elbow be the same size... ie interchangeable?