Grab both sides at the front near the sunglass holder and give it a light tug, you will start to understand how it holds in. If I recall correctly, it snaps into another plastic bit mounted to the headliner and pulls right out, giving you access to the wiring.
I pulled it myself once doing some brainstorming in regards to my Radar Detector install.
I pulled it myself once doing some brainstorming in regards to my Radar Detector install.