38 C.F.R. § 36.4217
Any notice required by the § 36.4200 series to be given the Secretary must be in writing or such other communications medium as may be approved by an official designated in § 36.4221(b) and delivered, by mail or otherwise, to the VA office at which the guaranty was issued, or to any changed address of which the holder has been given notice. Such notice must plainly identify the case by setting forth the name of the original veteran-obligor and the file number assigned to the case by the Secretary, if available, or otherwise the name and serial number of the veteran. If mailed, the notice shall be by certified mail when so provided by the § 36.4200 series. This section does not apply to legal process. (See § 36.4282 .)
38 C.F.R. §36.4217