In separate large stock pot or dutch oven, bring chicken stock and 4 cups water to a boil. Add ham and onion. After soup comes back to a boil, add potato flakes. Soup will stiffen up like you are making mashed potatoes. Add milk and tow coups water. I use the potato water. Add potatoes. When soup is hot, add salt and pepper to taste. Add shredded cheese. Stir to melt.