Cannot find the .fla but have the .swf

Sometime ago i created a flash website for a friend of mine and just the other day he asked me to make amendments on it. Unfortunately for the life of me i cannot find the .fla file. I do however have the .swf file.

Is there a way i can change the .swf back into the .fla so i can amend it??

I have looked high and low but cannot find this .fla file. Am i doomed?? Do i need to start the flash site again??

Is there anything i can do???