I can only guess: Twist Or Push twist Or Pull twist Or The entire faceplate may twist off, but has been painted shut. Another possibility is that the entire faceplate pulls down about an inch and is attached with clips that can then be released, removing the faceplate. But again painted sealed, you may have to run a razor around the edge to sever the paint, then try gently prying the plate down.

The entire faceplate pulls down about an inch and is attached with clips that can then be released, removing the whole unit. The bulb can then be unscrewed and removed.

As the trim has been painted and is sealed to the ceiling, you may have to run a razor around the edge to sever the paint, then try gently prying the plate down.