The Administration Hall

The Administration Hall is located on the next floor of the temple, just above the ordinance and sealing rooms.
A large portion of this floor is taken up by the the Celestial Room below. The other rooms include the Dome room, (named because it's taken up by the domed ceiling of the holy of holies below. It's used as a locker room for the general authorities to change into their white clothes), the First Presidency Room, the Council of Twelve Room, and the Seventy Room.
These rooms are used by the general authorities for weekly prayer and administrative meetings they hold in the temple.