342.2—Service of notice.
(a) Service.
The notice required by § 342.1 shall be served personally by an employee of the Government by delivery to the respondent, or by delivery to a person of suitable age and discretion at the respondent's dwelling house or usual place of abode, or by mailing to the respondent's last known address by registered or certified mail, return receipt requested.
(b) Proof of Service.
The post office return receipt, or the certificate of the employee serving the notice by personal delivery, setting forth the date and manner of service, shall constitute proof of service. In the case of a mentally incompetent respondent or a child under 14 years of age, service shall be made upon his guardian, near relative or friend, and the person so served shall be permitted to appear on behalf of the respondent.