TO ORDER REBUILT EXCHANGE UNITS OR PARTS,YOU MAY SIMPLY SEND US A PURCHASE ORDER VIA FAX OR EMAIL AND WE WILL SEND YOU THE ITEM. A CORE CHARGE WILL BE INDICATED ON THE INVOICE BUT, WILL BE CREDITED UPON RECEIPT OF A USABLE CORE. YOU CAN RETURN YOUR CORE IN THE SAME SHIPPING CONTAINER, OR YOU MAY SEND THE CORE IN ADVANCE ALONG WITH A PURCHASE ORDER AND WE WILL REBUILD AND RETURN THE ITEM WITH NO CORE CHARGE.