(i) The agreement to share personnel shall allow other participating districts to be substituted as the principal employing district. Notwithstanding any other provision of law, upon substitution of a new principal employing district, the shared employee shall be considered an employee of the new principal employing district with the same tenure status he or she maintained in such prior principal employing district. For any such shared employee for salary, sick leave and any other purposes, the length of service credited in such prior principal employing district shall be credited as employment time with such new principal employing district.

(ii) Where the principal employing district abolishes the position of a shared employee and creates a new position for the performance of similar duties, in determining the right of the employee under subdivision one of section three thousand thirteen or subdivision one of section twenty-five hundred ten to appointment to such new position, the new position shall be deemed similar if more than forty percent of the functions of the new position were performed by the shared employee in the shared position.

(iii) Where a participating district other than the principal employing district determines to discontinue the services of a shared employee pursuant to the terms of the agreement to share personnel, the employee shall retain his or her tenure rights in the principal employing district only. 3. School authorities of any school district sharing personnel pursuant to this section shall retain the right to promulgate educational or administrative policies pertaining to their respective school district pursuant to law, rule or regulation. 4. All agreements to share personnel pursuant to this section shall be subject to the approval and oversight of the district superintendent, if any, or by the commissioner or his designee if there is no local district superintendent. 5. The commissioner may promulgate rules and regulations to implement the provisions of this article.