If there isn't anything in the way just loosen the mounting and adjustment bolts and replace the belt.
Before replacing the belt after the old one is off, turn the alternator pulley by hand with a bit of side pressure and listen for any scratching/scraping/grinding sounds. (this will indicate possible wear on the bearings)
You MAY have to use a small bar against the alternator to get enough leverage to pull the belt tight before tightening the adjustment bolt.
Don't forget to tighten the bottom mounting bolt too.
Just be careful you don't pry against any part that may get damaged.
When done, start the engine any observe the belt and ensure it isn't slipping.
In a couple of days, with the engine off and ignition keys removed, inspect the belt for tension. (just put a bit of pressure on the belt at the half way point between pulleys, there shouldn't be more than 1/4" of slack)