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 422—MEDICARE ADVANTAGE PROGRAM > SUBPART B—Eligibility, Election, and Enrollment (§422.50 to §422.74) > 422.57—Limited enrollment under MA RFB plans.