I would give them a call...never hurts to try. If they can give you a seat, the reservations agent will do so. What flight are you on? If it is from the mainland on the 767, keep in mind that HA has 3 different seating configurations and thus can only assign seats that are common amongst all 3 configurations as specific aircraft are not tied to a flight until 24hours out. Some 767s have 234Y, others have 241Y and some have 246Y seats which means they can only assign 234Y seats. It may also be that your flight has all the common seats booked so you will have to wait unil OLCI when the non-common seats open up.