Increasing the value of a Smoothness Texture Map through code

Unity Engine
1

I’m having difficulty modifying the value of the ‘Smoothness’ texture map slider on an object through code in the ‘Standard’ shader. I’ve tried using rend.material.SetFloat(“_SMOOTHNESS”, 1); to see if this would affect the value but unfortunately, it doesn’t seem to work. Is there a keyword that I need to enable in order to be able to adjust the Smoothness value?

2

_Glossiness