Neb. Rev. Stat. § 25-1226

(1) A subpoena for a trial or deposition may be served by personal service, which is made by leaving the subpoena with the person to be served, or by certified mail service, which is made by sending the subpoena by certified mail with a return receipt requested showing to whom and where delivered and the date of delivery. Service by certified mail is made on the date of delivery shown on the signed receipt. (2) A subpoena for a trial must be served at least two days before the day on which the person is commanded to appear and testify. A court may shorten the period for service for good cause shown. In determining whether good cause exists, a court may consider all relevant circumstances, including, but not limited to, the need for the testimony, the burden on the person, and the reason why the person was not subpoenaed earlier.