Moving Posts to the top.

I need to know how to get posts to the top of the page from the middle. Not topics. I made a new topic that was really important and others posted after it. Someone deleted my post not the entire topic so I had to rewrite it and now its the 5th post in the topic instead of at the very top. It's too important to just rewrite it all and delete every other post that was there. Is there a way that I could move 1 post up to the top.