UPDATE: As of 3/13/2017 the credit, debit, and ACH (bank accounts) have been removed from the Travefy Expense tool. If you created a trip before this date, you will still have the option to use all methods of payment.
When you log into your account, click on Wallet on the right-hand side.
Next, click on Change and a new box will appear to enter your new bank account information. Once you are done, be sure to click Save Bank Account.