52 16... Removing and installing/replacing thigh support holder on front seat, left or right (sports/electric)

Necessary preliminary tasks: 

Move thigh support forwards fully.

Unfasten plug connection (1) and disconnect. Unfasten screws (2). Installation note:  Insert screws (2) with Loctite.

Fig 1: Identifying Plug Connection And Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Detach seat cover (1) in marked area from carrier (2) for thigh support. Feed plug out of carrier (2) for thigh support. Remove carrier (2) for thigh support.

Fig 2: Identifying Seat Cover And Carrier

Courtesy of BMW OF NORTH AMERICA, INC.