Illustrator Flattening issues

Does anybody know if it is possible, once you have created outlines and flattened the transparency, if there is any way to un-flatten it? I accidentally saved over the original instead of saving a copy, and realize now that I need to make changes to it. Is this even possible, or do I need to start over?

As far as I know, once you flatten and save that's it - any changes need to be made and your stuffed. It's a bitch, and something I've had problems with myself numerous times. No matter how much you try to remember to version save your files, there's always the one that slips through - and you can bet your house it's the urgent/big project one that does

dont know if this is relevent but in fireworls you save all your orginial work in .png format which keeps all the seperate layers and other bits of design, and then export them as jpeg or gif so you can upload them, if you then keep the png you can always go back to it, but it will take up disk space.

Hope that helps sorry if it doesn't