How to change the bulb in an enclosed ceiling light?
Most likely, it should pull down, out of the ceiling with relative ease. The trim will be attached to the fixture either with some long springs, or a lot of the newer fixtures have tabs along the side that hold it in.

If it is the spring type, there is a tool called a Recessed Can Light Tool that makes re-attaching these a bit easier, though they can also be reattached using a screwdriver or needle nose pliars.



Try not to twist it to much as you might just be tieing the springs into a knot unknowningly.