Center armrest (if so equipped)
Nissan Altima / Nissan Altima Owners Manual / Safety—Seats, seat belts and supplemental restraint system / Seats / Folding rear seat / Center armrest (if so equipped)

Pull the armrest down until it is horizontal.
See also:
Operating tips
● When the engine coolant temperature and
outside air temperature are low, the air flow
from the foot outlets may not operate for a
maximum of 150 seconds. However, this is
not a malfunction ...
Maintenance requirements
Your NISSAN has been designed to have minimum
maintenance requirements with long service
intervals to save you both time and money.
However, some day-to-day and regular maintenance
is essential ...
Checking seat belt operation
Seat belt retractors are designed to lock seat belt
movement by two separate methods:
● When the seat belt is pulled quickly from the
retractor.
● When the vehicle slows down rapidly.
...
