I would like to update my payment information.

Sure thing.  Once you are logged into your homepage, under the "My Account" heading on the right side, you will see a menu item called "Manage Payment Info". Click on that link to review and edit your payment information.   The landing page shows your current payment information and what gifts are being paid by it.   If you would like to replace this information with new information, simply start keying in the new information over the old and click the blue button “Pay ALL my gifts using this payment method.” The old is gone!   There are also tabs to add an additional payment method, whether it be credit card or bank account.