I have found a free Flash Decompiler, This can allow you to do many things. Like fix lost or corrupted files by turning the swf file into a FLA and convert flash formats (like flash 8 to CS6 and CS6 to flash 8). Although Be responsible with it because it could be used with illegal intentions like to get copyrighted material.
I hope you enjoy ;)
Link: https://www.free-decompiler.com/flash/
and yes im aware this site looks extremely sketchy...