Haw. Code R. § 16-181-13
If notice is not provided in the manner set forth in section 16-181-12, or if the notice provided is defective in any other way, and all parties nevertheless appear at the hearing, the arbitrator shall inquire on the record whether such parties are willing to waive their rights set forth in section 16-181-12. If the arbitrator is satisfied that an informed and intelligent consent is obtained from all parties who were not properly noticed, the hearing may proceed. If any party refuses to consent to a waiver, the hearing shall be continued with the proper notice of the rescheduled hearing provided to all parties. If the continuance results in the forty-five day deadline passing, each party shall sign a written statement agreeing to the extension of time.
Haw. Code R. § 16-181-13