Over ab rooflight

I am trying to remove the internal plastic cover surrounding the overhead cab light on my 2016 Nuevo. Does anybody know how to remove the six, three either side, blanking plugs, they cover the mounting screws. They seem to be the same type as used on automobiles, ie. a central bit you push in, and then the whole plug can be extracted. I cannot get anything to move, and don't want to destroy them in the process. Thank You.