52 14... Removing and installing outer upper rail trim

Move seat backwards and upwards.

Unclip trim (1) towards front.

Fig 1: Removing Outer Upper Rail Trim

Courtesy of BMW OF NORTH AMERICA, INC.

Driver's seat only: 

Feed trim out of seat mechanism:

1. upwards,
2. slide towards rear

Feed out trim.

Fig 2: Feeding Trim Out Of Seat Mechanism

Courtesy of BMW OF NORTH AMERICA, INC.