Start by turning the seat angle adjusting knob clockwise so that the seat is leaning all the way forward. This is necessary for clearance.

Using a phillips head screwdriver, loosen the single screw holding the seat back at the bottom of the seat.

Remove the seat back by sliding it downwards towards the floor. Once it is approximately 50-70% down, it should clear its tracks with enough space to facilitate removal by pulling down and towards the rear seat. It should come out very easily.