N.D. Cent. Code § 54-09-07
If an agent other than the secretary of state has been appointed for receipt of service, but the affidavit of a sheriff or of an adult who is not a party to a proceeding establishes that diligent inquiry has been made and that personal service cannot be accomplished upon any registered agent, officer, or superintending, managing, or general agent of an entity, then the secretary of state may be deemed the agent of the entity for receiving service of process. Service on the secretary of state must be made as provided in section 10-01.1-13. Except as otherwise provided by law, if the secretary of state is appointed as agent for service of process for any individual under any provision of this code, then service on the secretary of state and the responsibilities of the secretary of state with respect to the service shall be made or executed in the manner provided in section 10-01.1-13, to the extent practicable.
N.D.C.C. § 54-09-07