40 ILCS 5/15-154.2: Waiver of service and benefits.

A participant or annuitant may elect to waive all or any portion of his or her service credit and benefits which may be payable under this Article; however, service purchased under the provisions of subsection (c) of Section 15-113.1, subsections (b), (c) and (d) of Section 15-113.5, Section 15-113.6, and Section 15-113.7 must be waived before other service which is granted under this Article.