Could winner request new winner?

You can tell the giveaway creator that you don't want the game and he can ask for a reroll on that basis. But if you don't want a gift from someone, then just don't enter their giveaways.

yeah, seriously. Don't do it. Just say no.

If you accidentally entered, or the issue happened after you entered, just tell the GA creator you don't want it and that s/he should request a reroll.

I entered once in a giveaway of a game I wanted. But for some reason, I coudn't activate the game (was a Grid 2 "ROW" key). So I asked for a reroll, and the GA did so. I guess it's okay under very specific circumstances

Write comment on GA where you allow reroll as you don't want game. I wouldn't write reason in this case, since it's close to callout. And drama.
That should be enough for GAMaker to ask for reroll.

I just win on the game i just found myself purchase key so i ask he to reroll the winner.
The problem is every GA after winner annouce should show reroll entries from GA creator too.

Thank you all for answers ^___^
Have a nice day!