I have changed my plans and have 2 non-refundable tickets that I can't use now.

Is there anyway to cancel the tickets and bank any money for future travel or does each ticket need to be re-ticketed separately? (One of the tickets value is less than the $150 fee and isn't worth rebooking on its own.)

If not, can I change a one way flight from a-b to a multi-city a-c-d-b? (I can't seem to do it via the online "change flights" for the same new ticket price as the multi-city prices out.)

Thanks.