42 C.F.R. § 423.643 Effect of contract determination.
Title 42 - Public Health
The contract determination is final and binding unless— (a) The determination is reconsidered in accordance with §423.644 through §423.649; (b) A timely request for a hearing is filed under §423.651; or (c) The reconsideration decision is revised as a result of a reopening under §423.668.
Title 42: Public Health
PART 423—VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT
Subpart N—Medicare Contract Determinations and Appeals
§ 423.643 Effect of contract determination.

