Lexus 2003 LS Owner's Manual page 179

16L169a
4. To remove the convertible seat, press the buckle–release
button and allow the belt to retract completely. The belt will
move freely again and be ready to work for an adult or older
child passenger.
COMFORT ADJUSTMENT
(C) Booster seat installation
16L308
A booster seat is used in forward–facing position only.
165