I don't think that you'll get your characters changed from alt to main. Once you've selected your main character you'll stick to it. Also, all your alternatives will be stuck as alts even if you delete your old main. So to make a new main character you need to delete your old main, and then create a completely new char to be able to set is as your main.
Besides, unless your main is lvl 15, and alt is gen 75 and lvl 35, your loss isn't that great. You can transfer any items you want between your characters, and upon retiring you can change your name. So it can't possibly be that bad.
