I only have an old w124 car, and its power headrests are probably no where near the sophistication level of you car. However, on our car there is a recessed button on the seat back you can push to remove the headrest completely.

You can just push the power headrest button and lower it?

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2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro