Simply go to your orders dashboard and click on the “Payment Options” button. This will take you to a list of your saved cards where you can add, remove, and set your default. Autoship payments will be charged to the default card with the default billing address (in your account settings page), and be sent to you default shipping address (also in your account settings page). If there is only one card, then it is automatically set as the default. If there are more than one card, then the cards that are not set as your default payment method will have a button next to them that says “set as default”.