Advice to UA Flyers NRT-SIN in C. Check your seat assignments. When I booked I was able to reserve my favourite seats in the mini C cabin. However when I checked today, my seats have been changed and I'm back in the main C cabin. Apparently the plane has changed to a 777XP. But not only is there no 8A,8B,8H,8J, there is also no 9A,9B! According to seatguru & SeatExpert there should be 9A,9B, but these don't exist either.