If you have multiple accounts, and you want to consolidate your bills, go to the Account Administrators page and use the "Change Billing Contact" button. A confirmation email will be sent to address of your new billing contact, who will now receive the bills for your Pobox account.
If you have one account, but want another non-Pobox customer to be responsible for paying the bill, please fill out the billing contact form.
If you have two accounts, and only want one account that includes all the Pobox addresses, use our help page How can I consolidate 2 accounts into one?