Arrange chicken pieces in crock pot. Combine lemonade, brown sugar and ketchup and mix well. Pour over chicken. Cover. Cook on high 3-4 hours or low 6-8 hours. Remove chicken from pot, cover to keep hot. Transfer liquid to saucepan. Skim fat; combine cornstarch and cold water and add slowly to liquid, while stirring over low heat. When thickened, serve with chicken over hot rice. Serves 4-6.