Sorry if this has been asked before, but couldn't find an answer. Here's my situation: I booked the following itinerary:

IAH-CLE Class Y
CLE-IAH Class Q
IAH-GRU (Sao Paulo, Brazil) Class Q
GRU-IAH Class U

I flew the first 3 legs, but had to change my routing home. CO didn't have any flights available when I needed to come home, so I cancelled the GRU-IAH leg & flew Copa on a new ticket. I called my travel department & asked how much $$ I had available from the GRU-IAH cancelled leg to apply to a future (domestic) ticket. My TA said that Continental will only offer a voucher for the same routing in the future, and I'd pay the change fare too, so it would probably be useless for me to even try to use it.

I totally understand that it's non-refundable and I have a change fee. But can't I use the residual amount of the ticket for another ticket other than GRU-IAH? Also, any way of finding out the change-fee for the ticket? I looked at my booking on CO and my reservation from the TA and cannot find it.

Thanks!