I have a leak in one of the joints on my pcv pipe that is been installed between two elbows..How do I take off ??

There are a few reamers on the market that can ream out an elbow but many plumbers don't even buy them. Cut out the bad section and weld in new with PVC glue.

Is it flexible pvc or rigid? I find the flexible can be removed easily by using a sheetrock knife and cutting through the flexible pvc pipe to the inside of the fitting, don't overdo it and cut groves in the fitting if you are going to reuse it, Then work a small screwdriver behind the flexible pipe and pop it up Sometimes taking a small strip 1/4" to 1/2" wide works best and then start working around it with the screw driver. If it is a small fitting you can use a wood bit to ream out the old Flexible PVC. Rigid PVC is to difficult to remove and quicker to just cut it out.