Need to replace the alternator

Slide a 15mm socket wrench into the narrow space between the engine wall and the tensioner pulley bolt. With the wrench in the "tighten" position, pull the wrench toward you. This will loosen the belt. To put the belt back on, have the belt ready to go except for around the A/C compressor. Hold the wrench tight in your left hand, and "slip" (read: work!) the belt onto the A/C compressor with your right hand. NOTE that the most difficult part is getting the wrench inserted between the engine wall and the idler pulley nut. You may want to buy a "butterly" socket set to make it easier.

There should be a spring loaded pulley with either a nut or a square hole for a socket drive to turn it and take the spring load off of the belt while you change it.