If you were given a life do-over card, would you keep it or give it to a friend? If you kept it, would you prefer to be born to the same or different parents? Would you want to keep your memories?
I'd keep it, most definitely. I can only think of one friend who's managed to screw up his life anywhere nearly as badly as I've screwed up mine.
I wouldn't trade my parents in for anyone. I would definitely keep my memories; that's the whole point of a do-over, right? "Putting things right that once went wrong", as they used to say on Quantum Leap.
If I had to limit myself to one, specific change, I'd have stayed in the Coast Guard and gone to Marine Science Tech school. I could have spent the last two decades actually doing Real Science That Made A Difference instead of pissing around struggling to get a science degree that I don't know how to apply.
If I kept my memories, I could still meet the people who mean the most to me.
And the one who made me happy.