If at the date set for hearing, it appears that any person entitled to notice has not been properly served with notice, the board may postpone the hearing and set another time for the same not less than thirty days from the original hearing date. Notice of hearing shall be served on such omitted parties in the manner provided in sections 468.15 through 468.18. By fixing a new date for hearing and adjourning the proceeding to the new date, the board shall not lose jurisdiction of the subject matter of the proceeding nor of any parties already served with notice.
89 Acts, ch 126, §2
CS89, §468.20