Per What if I entered the wrong bank account for direct deposit?, you can contact the IRS (800-829-1040) if the refund hasn't yet posted. You can ask to stop the direct deposit, and they'll mail you a "CP53E notice", which will allow you to provide a different bank account for your deposit. If the account number was mis-keyed, they direct deposit will likely be rejected and they'll mail you the CP53E notice automatically.
