Heat vegetable oil in large nonstick skillet over medium heat. Add potatoes and cabbage; spread into an even layer. Cook 5 minutes. Stir well; spread evenly again. Cook 2 minutes longer. Remove from heat. With pancake turner, gently scrape loose from bottom of skillet. Stir in corned beef and cheese.
Beat eggs, milk, ketchup, salt and pepper in bowl. Pour over potatoes. Cover; cook over medium-low heat 7 minutes or until egg mixture is set.
Loosen around bottom and sides with pancake turner. Invert onto serving plate. Serve.