A police officer who participates in the defined contribution plan under this Section may not earn creditable service or otherwise participate in the defined benefit plan offered by his or her employing municipality, except as an annuitant in another fund or as a survivor, while he or she is a participant in the defined contribution plan. The defined contribution plan under this Section shall not be construed to be a pension, annuity, or other defined benefit under this Code.
A police officer who has elected under this subsection to participate in the defined contribution plan may, in writing, rescind that election in accordance with the rules of the board. Any employer contributions, and the earnings thereon, shall remain vested in the police officer's account. A police officer who rescinds the election may begin participating in the defined benefit plan on the first day of the month following the rescission.
40 ILCS 5/3-109.4