I had to do this to adjust the top to fit against my windows better. It is relatively easy to do. Lay the town down upside-down, so the headliner is facing up. The at the top near the front end the rubber molding flips in, in a U shaped cap over the end. Flip it out then just lightly pull it out of the metal track. I only pulled it out half way so I am not sure if there are any problems pulling it out all the way. Then to get the rubber back in just push the back into the rail and then I used a flat head screwdriver to push the front back into the metal rail.
Also you can remove all the plastic, and probably the headliner if you want by lightly pulling up. The metal clips should pop out, and it is easier if you slide your hand under the plastic and pull directly around the clip.
Hope this helps!
