Be careful not to screw up your headliner.
This is what I did. Get a screw driver flat blade very thin, but 1/4 wide. STick it in the side and there are two detents one on each side. Get one of them out and then the rear view will slide out if you pull it to the sides of the car.
I can take pictures if you want or your mercedes benz service manual library shows detailed pictures of it.