How can Igo back and Chang my checking account number from last year?

When comes to the page with the last years checking account info already show and the box is marked that is your preference, just look below that box of info and it says new checking account. click on that box and it will take you though how to input the new account. 

I just got off that page with my new account imputed and the old one erased

Please follow the steps in the below TurboTax FAQ for assistance with changing your transferred direct deposit information: 

https://ttlc.intuit.com/community/accessing/help/how-do-i-change-my-transferred-direct-deposit-information/00/27040