[Code of Federal Regulations] [Title 20, Volume 2] [Revised as of April 1, 2006] From the U.S. Government Printing Office via GPO Access [CITE: 20CFR418] [Page 1193] TITLE 20--EMPLOYEES' BENEFITS CHAPTER III--SOCIAL SECURITY ADMINISTRATION PART 418_MEDICARE SUBSIDIES--Table of Contents Subpart D_Medicare Part D Subsidies Sec. 418.3620 What is the effect of an initial determination? An initial determination is binding unless you request an appeal within the time period stated in Sec. 418.3630(a) or we revise it as provided in Sec. 418.3678.