(a) A conservatorship order must be served personally to an officer or director of the credit union by the commissioner, the deputy commissioner, or another person authorized by the commissioner.
(b) Service may be by mail if an officer or director is not available for service on the date personal service of the order is attempted.
(c) Service by mail must be by certified or registered mail, must be addressed to the credit union at the address shown for its principal office by department records and to the home address of the chairman of the board, and is complete on deposit of the order in a postpaid, properly addressed wrapper, in a post office or official depository under the care and custody of the United States Postal Service.