You can't find the switch? That's nothing. We are missing information on the whole cooker: make and model!
We could also do with a brief, clear, brief and concise description of the problem you are trying to solve
xxx, December 2015
You wish to reset the grill on an unspecified gas cooker using a red switch that you can't find?
You really should try harder....
And why do you need to reset the grill?
What does it mean reset the grill?