Except as otherwise provided or authorized in this act,¹ service of any notice, petition or other pleading, citation, summons, subpoena, order of the Commission of which service is required, and execution, commitment or other process, in any proceeding before the Commission under the provision of this act, may be made by the Proration Umpire,² his assistant or any deputy to the Proration Umpire, or by any other person authorized and directed by order of the Commission to make such service, and such service may be made upon any person, firm, trust, association or corporation, required to be served, in the same manner as is provided for the service of summons in civil actions in the district courts of the state, upon such persons, firms, trusts, associations, and corporations respectively. The officer or other person making any such service shall make his return thereof and file the same with the Secretary of the Commission. Said return shall show the time when the notice, pleading, citation, petition, summons, subpoena, order of the Commission, execution, commitment, or other process was received by him and the time and manner the same was served by him.