Did you already file? Then it's too late to change it. If the bank rejects your deposit the the IRS will mail a check to the address on your return.
Otherwise if you have not filed yet you can change your refund method and bank info by going through the File tab again.
Change your bank account
You did not say---but if you are wanting to change banking information because you are anticipating a second stimulus check, you do not change your information with TurboTax for that. Congress has not voted on a second stimulus check. If and when they do, there should be guidelines from the IRS about providing new banking information.