Originally Posted by
Quokka
You don't need to call UA (let alone UA Japan) to get seats assigned if you have a UA 016 ticket AND the NH segments are UA codeshares. NH phone agents can assign seats for such tickets. I've done this several times, with yesterday being the most recent
Like you, I too fly extensively on UA and NH. Coincidentally, my most recent call to NH (Tokyo) was yesterday as well to get seats assigned. The NH agent could not assign seats and told me to call UA.
It doesn't happen all the time (to be honest I don't know why) but it has happened more than several times to me. And when it does happen that NH cannot assign seats (a giveaway is you cannot assign seats via the NH website), call UA Japan.