This question is an exact duplicate of:
I made a mistake. I flagged a post I shouldn't have. It's not the end of the world, presumably the moderator will see it was a poor judgement call (I hope) but why can't I "go back" and delete my flag?
It seems silly to flag the same post to say: Please ignore my first flag.
Or can I do exactly that?
Related Feature request: unflag but aren't invalid flags something else entirely?
And one last question, what happened to the highlighted number that used to reside next to our profile avatars, the one that requested our attention?