Creating Free-of-Charge Subsequent Deliveries
Prerequisites
To create a free-of-charge subsequent delivery, you have to refer to an existing sales document, such as the:
Procedure
Use the same procedure that you use for
creating sales orders. Use order type FD in the standard system 
You do not have to use Create with reference for free-of-charge subsequent deliveries if you enter the order type and then choose Enter. A dialog box appears where you can enter the number of the order.
Result
After you have
released the free of charge subsequent delivery, you can create the delivery.