Yeah, I had to do this too. Being the whimsical idiot that I am, I used mine and went Elezen for some gods-unknown reason. Thankfully, my adorable little Miqo'te rage machine is back as herself. Thankfully, they're willing to undo the mistake once. I totally would have bought a second phantasia to change back. Oh, and it took like a week for them to get back to me.
I'm better than you.
