I think the whole bulb should just be gently pulled out - that's how mine are anyway.

Just to be safe, cut the power to that line first, that way if you do get out the tool box and start taking apart the housing you are not ruining any risk of a shock. But I can see clearly 2 slotted channels on the inside which indicates it should just pull out, not screw out. Worth a try anyway :-]

Thanks for the recommendations!