When you have an alternate payment method selected and if your primary payment method does not process, for example, if the credit card has expired, then your alternate payment method is used.  You must have more than one Payment Method added to your account before you can designate an alternate payment method.  Follow the steps for adding a new payment method for each payment method you want to add in your account.
 

To Designate an Alternate Payment Method

1. Log in to your Account Manager.
    
2. Expand the My Account section on left side of page by clicking on it.
    
3. Under this My Account section click Credit Card & Payment Info.
    
4. Above and to the right of the Payment Methods list, click Alternate Payment Info.
    
5. In the Payment Methods list, select the payment method you want to designate as your alternate, and then click Update Alternate Payment.