If you have multiple billing and/or shipping addresses and you need to make a change to the default billing or shipping address in your account, please follow these steps:
Login (or Register for a GoVets account)
Go to your Address Manager
Select "EDIT" for the given address that you want to setup as a Default Billing or Shipping Address.
On the following page, you will see the following two options on the bottom of the address:
Use as my default billing address
Use as my default shipping address
Make your selection and then "SAVE" the address.