(a) A limited partnership's registered agent is the limited partnership's agent for service of process, notice, or demand required or permitted by law to be served on the limited partnership.

(b) The secretary of state shall be an agent of a limited partnership upon whom any process, notice, or demand may be served when:

(1) A domestic or foreign limited partnership authorized to do business in this state fails to appoint or maintain a registered agent in this state;

(2) Its registered agent cannot be found with reasonable diligence;

(3) A foreign limited partnership transacts business or conducts affairs in this state without first submitting an application for registration with the secretary of state; or

(4) The registration of a foreign limited partnership has been cancelled.

(c) Whenever a domestic or foreign limited partnership authorized to do business in this state is an employer within the meaning of the Workers' Compensation Law, compiled in title 50, chapter 6, and the limited partnership is, for the purpose of workers' compensation, self-insured or a part of a self-insurance pool as provided in title 50, chapter 6, part 4, the limited partnership shall, for workers' compensation actions only, be required to appoint the commissioner of commerce and insurance and the commissioner's chief deputy, or their successors, as its true and lawful attorneys upon either of whom all lawful process in any such action or legal proceeding may be served, as is required of insurance companies by title 56, chapter 2.

(d) This section does not prescribe the only means, or necessarily the required means, of serving a limited partnership.