As long as you have not yet filed, you can make the changes under File tab. If you have already filed, it is too late to make changes. You have to wait until its accepted/rejected. If rejected, you can go back into the file section and make the changes.
Once your e-filed return has been accepted, it's too late to change your payment method in TurboTax. Instead, call the IRS e-file Payment Services right away at 1-888-353-4537 – they're open 24/7
https://ttlc.intuit.com/questions/2603038-how-do-i-change-my-refund-method