If you have not filed your return yet, you can update your direct deposit information in the interview to file to your return. In the file your return interview you will get to a screen that asks how do you want your refund, choose by direct deposit, then you can update your banking information.
If you have already filed your return, you cannot make changes to your return. You would have to wait until your return is accepted or rejected, which won't be until the IRS opens their system on January 23rd. Also, see the following
What if I entered the wrong bank account for direct deposit?
https://ttlc.intuit.com/replies/3302459
