GMC Yukon Owner's Manual page 22

Removing the Rear (Suburban Third Seat)
If your vehicle has a rear seat, it can be taken out for
more cargo space.
Before removing the seat, unlatch the outside passenger
position safety belts from the seat frame.
To unlatch the safety belt,
press the tip of a key into
the release hole of the
safety belt attachment
while pulling up on the
safety belt.
Then, hang the latch plate
end of the belt on the hook
at the top of the retractor
cover, out of the way.
To
remove the seat, fully open the rear load doors and
enter the back of the vehicle.
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