If you have already e-filed your return and it was accepted, you will be unable to change your banking information and your refund will not come via direct deposit if the account information is incorrect. However, don't worry! You should receive notice from the IRS when they cannot complete the direct deposit and this notice will come via US Mail. This notice will let you know that a paper check should arrive shortly. Please see the following link for more info on the IRS notice you will receive: https://www.irs.gov/individuals/understanding-your-cp53a-notice
Please see the below TurboTax FAQ for additional information:
https://ttlc.intuit.com/replies/3302459
