How does one remove the reading lamp?

My 2005 LaCrosse has a roof leak. I suspect the OnStar antenna. I think I could get at it from inside by removing the Reading Lamp assembly. What is the procedure to do this? Thanks a bunch.

iteresting post, my 05 leaks from the onstar antenna also. fortunatly i live in central texas and it doesn't rain that much. -i'm not sure how that lamp comes off except perhaps a special tool to 'unclip' it. removing the 'antenna' didn't do me any good. I plan to take it to a local body shop and let them deal with it. would be interested to see if you get an answer.

I finally got it. The lenses from the map light snap out. Then there are 3 screws (Robertson head, the square recessed ones) that hold the map light. After removing the map light the bolt that holds the OnStar antenna could be removed. I cleaned and dried under the antenna and hopefully sealed it using some 3M clear automotive sealer.

Awesome, thanks so much for the info, I'll give that a go & let you know!

Here's how I fixed this problem in 15 minutes:

Used a #1 flat screw driver to gently pry down on each lens along the center line where the 2 lens meet. There are 2 clips on each lens at the ends of the center line.
Remove the 3 square-head screws holding the lamp assembly. I think they are #2.
Remove the 10mm antenna anchor bolt and metal force plate to expose the antenna base which has 2 plastic retention fingers that prevent the antenna base from moving through the roof hole.
Compress the retention fingers with a screw driver or needle nose pliers while gently pressing upward on the antenna base.
In my case, the leak was at the plastic positioning pin location, not at the bolt. So I just placed a small rubber o-ring that fit snuggly around the positioning pin and reassembled the antenna. I figured this was better than applying sealant, as sealant would be much harder to remove in the future if the need should arise to do so.
Hose test and car wash test and no leak.