Question For Ticket/res Agents

USFlyer

Veteran
Aug 19, 2002
2,084
292
I asked this quite a while ago but need a quick refresher: Consider I have two wholly unused tickets, both nonrefundable. Can I combine these tickets to purchase a third nonrefundable ticket? My travel agent is telling me you can only exchange one ticket for another, yet I really seem to recall using two unused tickets to puchase a third in the past. (All tickets are US Airways tickets.)