Retriving Actionscript from swf

I have a quick question, not sure if it's possible but at work I'm working with a flash file thats 3 years old that we have to add special character support too. Problem is we don't have the lastest version of the fla.

Does anyone know of a way/app that can get the actionscript from a swf so I can compare it to the as in the lastest fla I have.