110 ILCS 805/3B-5
If a dismissal of a faculty member for the ensuing school year results from the decision by the Board to decrease the number of faculty members employed by the Board or to discontinue some particular type of teaching service or program, notice shall be given the affected faculty member not later than 60 days before the end of the preceding school year, together with a statement of honorable dismissal and the reason therefor; provided that the employment of no tenured faculty member may be terminated under the provisions of this Section while any probationary faculty member, or any other employee with less seniority, is retained to render a service which the tenured employee is competent to render. In the event a tenured faculty member is not given notice within the time herein provided, he shall be deemed reemployed for the ensuing school year. Each board, unless otherwise provided in a collective bargaining agreement, shall each year establish a list, categorized by positions, showing the seniority of each faculty member for each position entailing services such faculty member is competent to render. Copies of the list shall be distributed to the exclusive employee representative on or before February 1 of each year. For the period of 24 months from the beginning of the school year for which the faculty member was dismissed, any faculty member shall have the preferred right to reappointment to a position entailing services he is competent to render prior to the appointment of any new faculty member; provided that no non-tenure faculty member or other employee with less seniority shall be employed to render a service which a tenured faculty member is competent to render.
110 ILCS 805/3B-5