The salary of any district superintendent, assistant district superintendent or other professional employe in any school district may be increased at any time during the term for which such person is employed, whenever the board of school directors of the district deems it necessary or advisable to do so, but there shall be no demotion of any professional employe either in salary or in type of position, except as otherwise provided in this act, without the consent of the employe, or, if such consent is not received, then such demotion shall be subject to the right to a hearing before the board of school directors and an appeal in the same manner as hereinbefore provided in the case of the dismissal of a professional employe.
24 P.S. § 11-1151