Ford Fiesta Owner's Manual page 90

Moving the Seat Backward and
Forward
WARNING
Rock the seat backward and forward
after releasing the lever to make sure
that it is fully engaged in its catch. A
seat which is not fully engaged in its catch
could move when your vehicle is moving.
This may result in the loss of control of
your vehicle, serious personal injury or
death.
Seats
Adjusting the Lumbar Support
Adjusting the Height of the Driver
Seat
88