At the gas valve there should be a knob(on top) showing positions On...Off... Lite. Just turn it to the off position.But before you do make sure the instructions are on the valve to relite the pilot.Usually you press that knob down and hold it for a min. or so while you lite the pilot and it must be held down untill the thermocouple is hot ( at the proper temp.)Then release the kmob to the ON position .Hope this helps.