I assume you are referring to the rear view mirror over the windshield. It's not too difficult. The mirror is held into the base by a spring loaded friction catch. Sitting in the passenger seat --- not necessary to use seat belt. Grasp the mirror firmly in both hands --one on each side of the center post. Pull downward and slightly toward yourself. A short sharp jerk works better than a slow pull. There is an electic wire inside the connection that simply unplugs from the mirror. If this is the first time the mirror has been removed since new it may be a bit stubborn but it will come out.

Hope this helps.