Pull the main Sensor piece off the ceiling so only the ceiling plate is still attached to the ceiling
If the ceiling plate is attached with command strips
Pull the tab that’s on the adhesive approximately 6 inches directly horizontal with the ceiling. Doing this will release the adhesive effect of the command strip and allow you to remove the Sensor without damaging the ceiling’s paint.
You can also try third party solvents that help remove adhesive to help. Follow their instructions and warnings.
If the ceiling plate is attached with screws, then use a phillips head screwdriver to unscrew the two screws attaching the ceiling plate to the ceiling