i think it may be a secret one. its actually not for me.
I had my bro and wife booked in E phx-hnl-phx. their hnl-iah cancelled and the agent could only confirm them on the hnl-ewr-phx flight. she sat them in 1 K and L so i assume the flight was full.
ill be sure they add their OP number just to see what happens. i think mines on the the record now b/c i get the notes and checkin notices.