To remove the headrest, raise it as far as it can go then press the release button (1) while pulling the headrest up (2).
To reinstall the headrest, put the headrest poles (3) into the holes while pressing the release button (1). Then adjust it to the appropriate height.
WARNING
Make sure the headrest locks in position after adjusting it to properly protect the occupants.
Kia Niro 2017 (DE HEV) Service Manual: In-car Sensor Repair procedures
Replacement
1.
Disconnect the negative (-) battery terminal.
2.
Using a remover, remove the crash pad side cover [RH] (A).
3.
Loosen the screw and remove the crash pad plate [RH] (A)
4. ...
Kia Niro 2017 (DE HEV) Service Manual: Lumbar Support Units Repair procedures
Removal
1.
Disconnect the negative (-) battery terminal.
2.
Remove the front seat back cover.
(Refer to Body - "Front Seat Back Cover")
3.
Disconnect the lumbar support motor connector (A).
...