Your banking information cannot be changed after your tax return has been filed and accepted.
Banking information does not go from TT to the IRS until you file your 2020 tax return and it is accepted. The IRS will begin to accept and process 2020 returns at the end of January 2021.
You enter/change banking information in the FILE section before you file your 2020 return. Changing it on the TurboTax site does not do any good until you file your return and the IRS processes your return.
If your check goes to a wrong or closed account, it will be sent back to the IRS and then the IRS will mail a check to the address on your tax return.
The address you used on your 2019 return is what the IRS has at this time so all you can do is put in a forwarding address with the post office so the check can get to you.
From the IRS:
Bank Account Information
No. To help protect against potential fraud, the tool does not allow people to change direct deposit information already on file with the IRS.
If we issue a direct deposit and the bank information is invalid or the bank account has been closed, the bank will reject the deposit. We will then mail your Payment as soon as possible to the address we have on file for you, and we will update Get My Payment to reflect the date your payment will be mailed. Typically, once the payment is mailed, it will take up to 14 days to receive the payment, standard mailing time.
This was published in the Wall Street Journal and begins to explain the timing and how these 2nd payments are going to occur:
"To avoid sending money during tax-filing season, Congress established a Jan. 15 deadline for making the stimulus payments. Eligible individuals who don’t receive a check or direct deposit by that date will have to request a $600 refund when filing 2020 tax returns. "
That means the IRS is going to have to change how the EIP form that ties to Line 30 works prior to opening up the submission window in late January..... and it's how they are going to ensure that there isn't any unintentional 'double dipping' (I get a stimulus payment and I fail to state that on my 2020 tax return)
The IRS has no Congressional authority to send out payments after January 15, 2021. The law further states this 2nd stimulus (like the 1st one) is an advance of the 2020 tax return - not the 2021 tax return!
Once we get past January 15, 2021, the only way the IRS has to get the 2nd stimulus to taxpayers is through the 2020 tax return ... it will be on Line 30 of the 1040.
Turbo Tax sent me an email stating that they tried to deposit my stimulus check into my account last year but it was rejected because my account was closed. Then they sent a link for me to log into my turbo tax account and update my account information. It told me make sure it was correct because they would only allow me to update it once and if it was rejected again they would have to send my stimulus back to the IRS.