How do I remove theses buttons/switches 65 Valiant?

OK, in the later models where the headlight switch and stem come out together... I you did ever get that knob and stem separated you would find what looks a little like threads on that triangular stem. It's not actual threads though, just barbs that bond the pot metal knob to the stem.
For this early model, I don't know. I would first look for the little release button on that switch.