Section 15. An appointing authority may, with the approval of the administrator or, if the appointing authority is a department, board, commission, institution or other agency within an executive office, with the approval of the secretary of such office, make a provisional promotion of a civil service employee in one title to the next higher title in the same departmental unit. Such provisional promotion may be made only if there is no suitable eligible list, or if the list contains the names of less than three persons eligible for and willing to accept employment, or if an eligible list has been established as a result of a competitive examination for an original appointment and the appointing authority requests that the position be filled by a departmental promotional examination or pursuant to section eight. No provisional promotion shall be continued after a certification by the administrator of the names of three persons eligible for and willing to accept promotion to such position.

If there is no such employee in the next lower title who is qualified for and willing to accept such a provisional promotion the administrator may authorize a provisional promotion of a permanent employee in the departmental unit without regard to title, upon submission to the administrator by the appointing authority of sound and sufficient reasons therefor, satisfactory to the administrator. If the administrator has approved the holding of a competitive promotional examination pursuant to section eleven, he may authorize the provisional promotion of a person who is eligible to take such examination, without regard to departmental unit.

A provisional promotion pursuant to this section shall not be deemed to interrupt the period of service in the position from which the provisional promotion was made where such service is required to establish eligibility for any promotional examination.

A secretary of an executive office who approves a provisional promotion pursuant to this section shall notify the administrator of each such approval. Such approval shall be made pursuant to the civil service law and rules, and such notification shall be made in such form as shall be required by the administrator. The administrator shall terminate any provisional promotion if, at any time, he determines that (1) it was made in violation of the civil service law and rules, or (2) the person provisionally promoted does not possess the qualifications or satisfy the requirements for the position. An appointing authority which makes a provisional promotion pursuant to this section shall report such promotion to the administrator.