Hi everybody

I'm traveling with my girlfriend and one of her friends to Singapore later this week. We are returning next Tuesday 27th via Tokyo. We booked a fantastic deal and are traveling on a K fare, but now I'm looking at the flights back from HND/NRT and there is R9 on pretty much every flight heading out of Tokyo to North America on the 27th. Is there any way to take advantage of this to use three of my GPUs? I tried the change my flight tool on the UA website and even if I type W then it still only shows me K fares in the results. Is it possible for them to waive the change fee if we kept exactly the same flights? Is it possible to do this at the last minute, for example at the airport?

Does anybody have experience with this? I've attached our flight details below. We would like to keep the SIN-NRT segment to that flight time so we can take advantage of a few hours in Tokyo