This document discusses how to copy line sets between sales orders in Oracle Applications Release 12. It explains that line sets can be copied when creating a return material authorization (RMA) by copying an existing sales order, but the original order must be at least booked. It also notes that the copy line set process does not support copying ship or arrival line sets from a sales order to an RMA. The document then walks through the steps to book a sales order and create an RMA by copying the booked sales order and checking "Copy Fulfillment Set" to successfully copy the fulfillment set to the RMA.