If you have already filed
You cannot change the information at this time. You will need to wait until your return is accepted or rejected (January 23rd, 2017 is when the IRS opens their e-file system). If your return is accepted,
you will not be able to make any changes. When the IRS tries to deposit
your refund to the account information on the return, it will check
that the name on the return and bank match. If it fails to match, then
you will automatically be switched to receiving a paper check for both the IRS (& State if any). If your return is rejected, you can then go back through the Interview on the File tab to make your changes.
If you have not yet filed
For the online editions of TurboTax click on File tab and go through the Interview. You will come to the screen where you can change your bank routing and account information.