If you have USD in your Swan account, you can send it back to your bank on file by clicking on "US Dollar Withdrawals" under the "Withdrawals" tab at the top.
Then, enter the amount that you'd like to withdraw and click "Continue". The USD currently available for withdrawal will be shown below. Not all of your USD balance may be available. Click the "available to withdraw" link to see your unlocking timeline.
Click "Confirm" to complete your withdrawal. Your USD will arrive back in your bank account in 1-3 business days.