2008 Sierra Headlamp replacement

How do you replace the Headlamps (Bulbs ) on a 2008 GMC Sierra Crew Cab.Is there an easy way to do this? I looked and found 2 screws holding the top part of the assembly. i removed them but the assembly will not come out. What did I missed?
Thanks

Andy

Open the hood, reach in and remove bulbs. Pass side, loosen air box to gain access. Tip - Use regular slip joint pliers to remove bulbs, easier access and less chance of skinning your fingers.

I was able to change all 4 of mine (PIAA hi-intensity) in about 15 min.......................