Once your return has been accepted (or mailed), it's too late to change direct deposit bank account information. If the information provided is for a closed or invalid account the government will mail you a refund check.
If your recently e-filed return is in pending status, wait to see if it is either accepted or rejected.
Now, for the anticipated stimulus check the details are still being worked out by the government at this time. We do not have information on how or if you will be able to update direct deposit information. Once things are finalized we will be able to provide more guidance. You can also stay updated by checking back on the following links.
https://turbotax.intuit.com/coronavirus/
https://ttlc.intuit.com/community/tax-topics/help/how-are-my-taxes-affected-by-covid-19/00/1330402