If you've already filed and your return has been accepted (or mailed), it's too late to change your bank account information. If the information you provided is for a closed or invalid account the government will mail you a refund check.
For additional information, please see the below TurboTax FAQ:
ttlc.intuit.com/community/refunds/help/what-if-i-entered-the-wrong-bank-account-for-direct-deposit/00/26213