1. I posted this question. I needed to quit TurboTax and reload it in order to get the "File an Amended return" button.
2. I was still frustrated that it would let me file an amended Federal return but not the state return. BUT, it turned out that I just needed to wait for my original state return to be accepted. Once I got the notice, I restarted TurboTax and was able to successfully file the amended Wisconsin State Return.
