42 CFR § 405.986 - Good cause for reopening.
(a) Establishing good cause. Good cause may be established when -
(1) There is new and material evidence that -
(i) Was not available or known at the time of the determination or decision; and
(ii) May result in a different conclusion; or
(2) The evidence that was considered in making the determination or decision clearly shows on its face that an obvious error was made at the time of the determination or decision.
(b) Change in substantive law or interpretative policy. A change of legal interpretation or policy by CMS in a regulation, CMS ruling, or CMS general instruction, or a change in legal interpretation or policy by SSA in a regulation, SSA ruling, or SSA general instruction in entitlement appeals, whether made in response to judicial precedent or otherwise, is not a basis for reopening a determination or hearing decision under this section. This provision does not preclude contractors from conducting reopenings to effectuate coverage decisions issued under the authority granted by section 1869(f) of the Act.
(c) Third party payer error. A request to reopen a claim based upon a third party payer's error in making a primary payment determination when Medicare processed the claim in accordance with the information in its system of records or on the claim form does not constitute good cause for reopening.