42 C.F.R. § 405.931
(a) Scope and basis. The provisions in §§ 405.931 through 405.938—
(b) Definitions. For the purposes of the appeals conducted under §§ 405.931 through 405.938, the following definitions apply:
Eligible party means a beneficiary who, on or after January 1, 2009, meets the following criteria, and is, thus, eligible to request an appeal under §§ 405.931 through 405.938:
(iv)
Eligibility contractor means the contractor who meets all of the following:
Processing contractor means the contractor responsible for conducting the first-level appeal and issuing a decision on the merits of the appeal. Appeals under § 405.932 are conducted by the MAC who, at the time of the referral of the request for appeal under § 405.932(d)(2), has jurisdiction over claims submitted by the hospital where the eligible party received the services at issue.
(d) Authorized representatives, appointed representatives, or representatives of a deceased eligible party. For the purposes of appeals conducted under §§ 405.931 through 405.938:
(1) The provisions of § 405.910 apply to an eligible party appointing a representative to assist in such appeal, as appropriate, except as follows:
(5) A beneficiary who is an eligible party is considered unrepresented if the beneficiary meets any of the following: