I am trying to fix a leaking diverter in my shower. How do I remove the old diverter? I have removed the knob, and cover. Thanks!

You didn't say so I'm going to assume that you have a three knob valve,(see image) and not a one handle one.
You already have the knob and the face plate removed. Now unscrew the large nut and back the stem and washer assembly out counterclockwise. Replace any worn and torn washers and check the seat for nicks or rough spots. If you find any, replace the seat. Good luck, Tom