CFR > Title 42 - Public Health > CHAPTER IV—CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES > SUBCHAPTER B—MEDICARE PROGRAM (parts 405 to 426) > PART 423—VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT > SUBPART N—Medicare Contract Determinations and Appeals (§423.641 to §423.668) > 423.656—Appointment of representatives.