5 USC 3318 - Competitive service; selection from certificates

(a) The nominating or appointing authority shall select for appointment to each vacancy from the highest three eligibles available for appointment on the certificate furnished under section 3317 (a) of this title, unless objection to one or more of the individuals certified is made to, and sustained by, the Office of Personnel Management for proper and adequate reason under regulations prescribed by the Office.
(b) 
(1) If an appointing authority proposes to pass over a preference eligible on a certificate in order to select an individual who is not a preference eligible, such authority shall file written reasons with the Office for passing over the preference eligible. The Office shall make the reasons presented by the appointing authority part of the record of the preference eligible and may require the submission of more detailed information from the appointing authority in support of the passing over of the preference eligible. The Office shall determine the sufficiency or insufficiency of the reasons submitted by the appointing authority, taking into account any response received from the preference eligible under paragraph (2) of this subsection. When the Office has completed its review of the proposed passover, it shall send its findings to the appointing authority and to the preference eligible. The appointing authority shall comply with the findings of the Office.
(2) In the case of a preference eligible described in section 2108 (3)(C) of this title who has a compensable service-connected disability of 30 percent or more, the appointing authority shall at the same time it notifies the Office under paragraph (1) of this subsection, notify the preference eligible of the proposed passover, of the reasons therefor, and of his right to respond to such reasons to the Office within 15 days of the date of such notification. The Office shall, before completing its review under paragraph (1) of this subsection, require a demonstration by the appointing authority that the passover notification was timely sent to the preference eligibles last known address.
(3) A preference eligible not described in paragraph (2) of this subsection, or his representative, shall be entitled, on request, to a copy of
(A) the reasons submitted by the appointing authority in support of the proposed passover, and
(B) the findings of the Office.
(4) In the case of a preference eligible described in paragraph (2) of this subsection, the functions of the Office under this subsection may not be delegated.
(c) When three or more names of preference eligibles are on a reemployment list appropriate for the position to be filled, a nominating or appointing authority may appoint from a register of eligibles established after examination only an individual who qualifies as a preference eligible under section 2108 (3)(C)(G) of this title.