Chevrolet 1997 Astro Owner's Manual page 18

4. Lift up on the left seat release lever, then the right.
The latches are near the floor on the rear legs of
the seat.
5. Lift up on the rear of the seat to remove the seat
assembly from the rear latch pins. Then, pull back
and lift the seat out of the vehicle.
Your seat release latch lever is sprung with a
two-stage mechanism. To fully release the latch, two
levels of lift effort will be required. First, a low effort
to overcome the first stage and then a moderate
effort to fully release the latch.
1-10