Delaware Code Title 25. Property § 722. Service of summons

(a) If a party, named in the summons for partition cannot be found in the county, to be served personally, service may be made by leaving a copy of the summons at the usual place of abode of such party within the county at least 6 days before the return day thereof in the presence of an adult person, or, if such party has no known place of abode within the county and cannot be served personally, and such party's appearance is not duly entered at the return of the summons, the Court shall make such further order for service of the summons as seems proper to it.

(b) In case it appears to the Court by the petition and affidavit or other proof at the hearing of the petition, that any persons interested in the proceedings other than the petitioners are nonresidents of the State and cannot be served personally with a summons in partition, an order may be made for the appearance of the nonresidents at a day to be fixed by the Court in order.  The day fixed shall not be less than 2 weeks after the date of the order.  The order shall likewise prescribe the manner of serving notice thereof on the nonresidents.