the rear bumper HAS to be dropped to get those middle rear reflectors out. The side ones can come off without taking the bumper off.
The middle ones have a screw on the back that holds them in while the side ones have a clip. So the screwdriver needs a place to go so the rear support bar blocks it. Taking the bumper down is actually quite easy. Like 3 bolts on each side, 4 clips in the middle, and a screw behind each taillight.
10 minutes tops to drop it down