Raise the back of the seat fully.

Remove screws across the bottom.

Using a small round screwdriver and a helper (the easier method IMO):
Have your helper sit in the seat pushing his/her back against one side of the seatback cushion to slacken the seat material on that side, insert the screwdriver shaft in the fold of material right where it wraps around and into the seatback, carefully pull the seat side material rearward and out of the slot in the side of the seatback, slide the screwdriver up and remove the material edge as you go.

Repeat on other side.

There is a hard-plastic edge sewn into the seat side material where it fits into the crimp/slot in the edge of the seatback, that simple.

__________________

Gone to the dark side

- Jeff