I have little experience in the business, but common sense tells me it takes longer to get new customers than it takes to loose old ones, so you're confronted with a fine balancing act. Nickrey makes a great suggestion on specials. Another idea might be for you to try to acquire new customers during off-peak periods by offering special menus during those times. It strikes a balance by trying to attract new customers while not alienating old ones and could be a source of creativity for you and growth for the owners. If you're able to demonstrate customer growth and loyalty with food to your own liking, you'll be better placed to convince the owners to allow you to expand. At the end of the day, it is all about $$$. Hope that helps...