Unfortunately once it's flagged for a change, you need to change it and it won't let you change it to the same name (as I'm guessing you've probably tried).

Your only really solution here is to change it to something else and then quickly buy a name change from the mogstation. I know it's far from a perfect solution, but it would get you back up and running again and I've never heard of SE "unflagging" an account from a name change (or if they have, no one has ever posted about it on forums/reddit that I've seen...)