The Business Partner Accounts tab allows you to manage the business partner accounts the customer is associated with. This tab is only available when working with a customer associated with a B2B account.
Choose BPA: Select this button to add a business partner account association to the user. A pop-up dialog box will appear. Use the dialog box to search for the appropriate business partner account, then select the "Select" box to the right of the account to add it to this customer. Dismiss the dialog when complete.
Business Partner List: The list of all of the business partner accounts this customer is associated with. Select the "Remove" icon to the right of an account to remove the association between the customer and that account.