The illustration is generic.
To lower the backrest:
Pull upward/forward on the handle located at the top of the outer seats in the second seat row.
Fold the backrest forward and slide the whole seat forward.
To raise the seat to the upright position:
Slide the seat backwards until it reaches the stop. The backrest must fall easily back into the correct position.
If the backrest in the centre seat row cannot be locked on its return after entry/exit, it may need to be moved forward again and then back with slightly more force.
Check that the backrests and head restraints in the rear seat are locked properly after being folded up.
The head restraints of the outer seats must always be raised when there are passengers on any of the rear seats.