763:
N685UA, former N590HA, ferried GYR-LAX 2714/28Apr.
My guess is N685UA will ferry to HKG after N684UA exits with high J Polaris/PE (STC for ex HAL aircraft).
Based on dates, looks like N677UA should be ready within a few days to exit HKG and a replacement unit into mod will provide enough released Y seats for all three HA units.
788:
N29907 entered XMN maint 2743/28Apr
789:
N26967 exited XMN maint 2742/29Apr