42 CFR §417.461

1. (a)Request for disenrollment.
   1. (1)A Medicare enrollee who wishes to disenroll may at any time give the HMO or CMP a signed, dated request in the form and manner prescribed by CMS.
   2. (2)The enrollee may request a certain disenrollment date but it may be no earlier than the first day of the month following the month in which the HMO or CMP receives the request.
2. (b)Responsibilities of the HMO or CMP. The HMO or CMP must—
   1. (1)Submit a disenrollment notice to CMS promptly;
   2. (2)Provide the enrollee with a copy of the request for disenrollment; and
   3. (3)In the case of a risk HMO or CMP, also provide the enrollee with a statement explaining that he or she—
      1. (i)Remains enrolled until the effective date of disenrollment; and
      2. (ii)Until that date, is subject to the restrictions of § 417.448(a) under which neither the HMO or CMP nor CMS pays for services not provided or arranged for by the HMO or CMP.
3. (c)Effect of failure to submit disenrollment notice to CMS promptly. If the HMO or CMP fails to submit timely the correct and complete notice required in paragraph (b)(1) of this section, the HMO or CMP must reimburse CMS for any capitation payments received after the month in which payments would have ceased if the requirement had been met timely.