https://ttlc.intuit.com/questions/3402261-how-do-i-amend-my-2016-turbotax-online-return is the instructions for amending, but I don't see the option in step 2. I only see what seems like starting a new 2016 return.
https://ttlc.intuit.com/questions/4003675-multiple-accounts
Sounds like you are in the wrong TT account.