If you unpublish, yes. If you REpublish, no.
Arc 55669 - Tales of the PPD: One Hell of a Deal (video trailer)
Arc 64511 - The Wrecking Ball
Arc 1745 - The Trouble With Trimbles
Arc 302901 - HappyCorpse
Once published, click it and hit the edit button. Do what needs to be done, save and close I think and it's fine. I think it might take a few for the changes to show up when you look at it though. I changed some of the intro text on mine, didn't see it, walked away and when I came back later it was there.
If you publish a story, then decide to edit it, will that reset your ratings?