2

Possible Duplicate:
Vote too old to be changed, unless post is edited “problem”

By mistake I downvoted good answer that was upvoted by me earlier. Now I cannot upvote it again because the answer is too old. I asked answer author to edit his answer and then was able to upvote it again.

Is there other way to repair such mistake?

I think SO should allow me to change my decision within some time, but maybe I omitted something.

1

It's designed to prevent people gaming the system - particularly downvoting other answers on questions they've upvoted. See this related question.