From the break down I saw, you ADJUST this model, not convert. If it's already set up for Propane, reverse the procedure to revert back to nat. gas. Reverse the regulator cap, then open up the orifices with a 1/2" open end wrench. You will also need to adjust the bake and broiler orifices also...also, there may be a setting on the thermostat. It'll be stamped with something like a L on top and a N on the bottom. Move it to N..wrench:)