In 3-quart saucepan, heat oil over medium-high heat. Add carrot and celery mix; cook 8 minutes, stirring frequently, until tender.
In small bowl, place 3 tablespoons of the broth; set aside. Stir remaining broth, the water and chicken into vegetables. Heat to boiling; add noodles. Boil 7 minutes or until noodles are tender.
Meanwhile, stir flour into reserved broth with whisk until smooth. Stir into soup. Cook 3 minutes, stirring constantly, until soup is slightly thickened. Stir in pepper. Garnish with parsley.