Not sure how the 1K line would treat it. I've called the 1K line and they've helped me out when flying an AC flight booked through some UA/*A contract my employer has, luckily my flight had a UA codeshare flight number.
Sometimes they can't do anything though.

I know NRT-IAD on ANA has a UA flight number, you could try them. I've also tried with other flights and had no luck and my employer's travel office had to deal with it. SQ is one where the airline though is much more helpful than the 1K line.

Try it, it may work, it may not. Best of luck.