Del. Code tit. 29, § 5921

The rules shall provide for the appointment of a person standing among the highest 30 on the appropriate referral list, to fill a vacancy, except as provided in § 5919 of this title. In no case shall the rules require the employing agency to give a reason for rejecting names on the list unless all names are rejected. When the appointing authority selects an applicant for hire from the list the applicant may, at the discretion of the appointing authority, start work immediately and be placed on the payroll forthwith and any additional approvals or paperwork required by the rules shall be performed subsequently.