Sarge

Depends on what 42 you are talking about, there is a 42-4, 42-3. If you have the 42-4, then like Brian said there should be a white strip at the front of the canopy, start at one end and pull down just a little and work your way down. If the strip is gone, then well be careful. The original acrylic were very thin .080 and if you pull down too hard you will bust it. When replacing the acrylic (getting new ones) make sure you get the molded canopy that is made of .100 The bottom acylic on the 42-4 has tension wheels on each side in the back of the bench, you need to loosen them to get the acrylic out.

If you have a 42-3 then you just take out all the plastic screws on the strip to remove.

There is no screw to loosen on the 42-4 like the other gentlemen said.

Good luck