I know there isn't button to do that, but is possible in the future the forum have that feature?
Because I've mistakenly reported my post to a moderator by accident.
I don't think there's a function for doing that, ones sent it will be received from the other end, same also applies to sending PMs, but in this PMs you can delete the message for yourself which means you can choose not to have a copy sent to you, reporting a post doesn't mean getting banned, you're only drawing the attention of the moderator to that particular thread for further necessary action.
So far, I reported 3 posts with 100% accuracy, 1 of the 3 reported is my post. I don't know how that 100% comes, because my post i did report some time ago, maybe still be unhandled or hasn't been seen by a moderator. (It might also a bug percent calculation)
Maybe the results seen was from the last one you have sent, also you don't need to worry as long as you're on point about the mistake you did in reporting, the comments made also goes a long way in explaining the purpose of the report made, example if you reported the thread to be moved, you're likely to end up on same accuracy, what you're reporting about matters here.