Rocker Switch on Salon Lights

[Desiderata]

Not sure if this is an "Electrical" question, or an "Interior" question. Anyway,

The rocker switch on one of the shaded salon lights has died. No big problem, except
I can't figure out how to get the #?!@$ light off of the bulkhead so that I can get at the inside.
I can't find a set screw that would hold it in place and it doesn't twist or turn.
So, before I resort to brute strength and a hammer, does have any input.

tks

Rick