There are some addresses you can manage and others that only customer support can manage. The ones you can manage are found in your Address Book. One way to find your Address Book is via your Invoice Settings. From your Tools section, click on the Invoicing link. On the Manage Invoices page, click on More Invoicing Tools, under Invoice Settings, look for Address Book. The rest is straight forward.
If you can't find the Address there, next step would be to contact customer support for additional assistance. This can be done via email, phone or through Twitter @AskPayPal or via Private Message on their Facebook page at https://www.facebook.com/PayPal
