You will need: T20 TORX wrench, flat blade screwdriver.
1. Remove the rear door upholstery and moisture barrier film (see «Removal and installation of an upholstery of a back door»).
2. Use a screwdriver to press the latches securing the inner handle to the door upholstery...
3.... and remove the inner handle of the lock drive.
4. Install the rear door lock internal handle and all removed parts in the reverse order of removal.