Upon arriving I spoke to the customer and she explained that her daughter had smelled gas so she wanted to get the furnace checked to make sure it wasn’t leaking. Customer took me down to the furnace and I explained what I was going to do to check for leaks. Performed check on complete furnace and found that the gas valve is not shutting all the way when it is supposed to, allowing a small amount of gas to leak out into the furnace. Advised the customer that the gas valve will need replaced due to it leaking and quoted her the price for that. Customer agreed with the cost and provided a 30% deposit for me to go and get the part. I left and went to get the part from the manufacture and returned to install it. Removed existing gas valve and installed new gas valve and tested furnace for proper operation. All components are operating properly at this time and there is no longer a gas leak coming from the system. Advised the customer on all services performed and she is satisfied at this