Join Date: Jan 2005
Location: New York, NY
Programs: UA, AA, DL, Hertz, Avis, National, Hyatt, Hilton, SPG, Marriott
Posts: 9,452
I strongly doubt you'll get a refund on a nonrefundable ticket in this case. While the CoC defines a configuration change as "irregular operations", that does not trigger a right to refund by itself. Any of the defined irregular operations first leads to an obligation for United to transport the passenger on its own metal to the destination or stopover point, followed by accommodation (at United's "sole discretion") on other carriers.
MAYBE you can make a case for EVA Y on the SFO-TPE flight, but I also have serious doubts about that approach.
In reality, there isn't much difference between 787 and 77W Y.