In most cases, once the IRS has accepted your return (or you've already mailed it), there's not much you can do.
If the info you provided is for a closed or invalid account, the government will mail you a refund check.
If you entered a valid (but incorrect) account number not belonging to you, usually there's nothing to worry about, as many banks won't deposit tax refunds into accounts where names don't match up. You can try calling the IRS to stop the direct deposit, if your return hasn't posted to their system yet (and you're willing to get your refund via paper check). For security reasons, the IRS cannot re-route your refund to a different account.
If you haven't filed yet, you can still change your bank account info for direct deposit.
On filed returns in pending status, wait until it's either accepted or rejected before taking action. If rejected, you can update your account and any issues that caused the rejection. Open your return in TurboTax and go through the File section again to update your bank account before re-submitting your return.