Purchased a UA non-refundable return economy ticket going MEL-SFO in May and returning SFO-MEL in September. I returned early to Australia using award miles to fly Air New Zealand and avoid $200 change fee. I know it is a nonrefundable ticket but is there any process to obtain a refund for unused taxes on the return portion of original ticket? There are approximately 3 weeks until my ticketed return date but I intended to just let the reservation lapse if no refund possible