To combine a back order with the order you are placing, follow the directions to validate the order. Select the back order you wish to add to and submit your order (this will appear on the right-hand side below the Order Summary). At this time, you may only add one back order to the order you are placing. Note: Your new order will be added to the existing back order you selected and this will reflect in your order history page. The order you are currently placing will reflect as cancelled combined with (order number).