After logging on to your account, click on the My Profile link on the left of the screen. From there, you can view, edit, and add new payment methods and use them to donate to different events.
Click the Edit icon to update your payment information. This will be applied to any event associated with that payment method.
You may only delete payment methods that are not currently being used for an active or recurring event.
Your new payment method will now appear in the list under Payment Information, and you may double-check your current events in My Account to make it has been applied appropriately.