How do I remove the rear spoiler to change the 3rd break light?

I just did this. There are four "screws" (on my car they are nuts). Two only accessible from under the inside trim, so you have to loosen that first. Also there are two plastic connectors that need to have the detents squeezed closed to permit the plastic retainer to slide through. The left one is a bit difficult because the trim is not easily removed completely because of the liftgate arm (I couldn't see an easy way to disconnect this). Easiest access is provided by pushing the trim up and working from underneath it. Also don't forget to disconnect the window washer hose prior to tackling the plactic connectors.