In SIHOT, each room requires a room holder for the room rate to be charged correctly. If sharers arrive and depart on different dates, the room holder may change to ensure that the occupied room is never without a room holder.
On the rooming list, SIHOT identifies the account holder with the lowest subnumber as room holder. In reservations without an account holder, the guest with the lowest reservation subnumber is considered to be room holder.