Step 5 · Remove the Old Angle Stop
This step requires two wrenches. Use one adjustable wrench (or channel-lock pliers) as a 'backup' to hold the copper pipe coming from the wall securely, preventing it from moving. Use the second adjustable wrench to grip the large compression nut on the back of the angle stop and turn it counter-clockwise. Once the nut is loose, you should be able to slide the entire old angle stop, including the nut and the old compression ring (ferrule), off the end of the pipe.