Guild Wars 2

Not as far as I know.

No. unless you are helping someone. I suspect that after your very basic question is a reason (hint- best is to tell what you want to do, not what you want to know :P).

If you want to relive the pleasure of the story and the sattisfaction, you can help someone else doing their instance (and you will be a guest there). You won’t get end rewards, you can’t make different choiches on your own personal story and you only get loot from defeated foes.

If you want to change your own personal story in a different direction then the answer is that it can’t be done. If you want a a different reward item the answer is also no.

I might have forgotten options to want to replay, so if not listed please ask away, if you ask what you want to do it is far more easier to answer