Lexus RX300 Manual page 91

COMFORT ADJUSTMENT
16R101
Move the seatback angle control switch backward to flatten the
seatback.
76
16R102
Push the seat position control switch downward to lower the seat at
the same level as the rear seat (driver's seat only).
CAUTION
D Do not allow passengers to ride on the flattened seat while
driving; use the seat in the normal position.
D After putting back the seat, try pushing the seatback
forward and rearward to make sure it is secured in place.
Be certain to replace head restraint.