100% certainty? There are definitely refundable V fares (though they're not likely offered all the time). I've most often seen them on short, one segment itineraries like SEA-PDX, but I also saw one once on SEA-SFO-SAN.

OP, I suggest you call reservations and ask what you can do with the remaining value on this ticket. That's really the best place to start and if they don't give you the answer you want then come back here, post all the details including the routes and we can tell you if we think the agent is correct or not.