40 ILCS 5/15-140
A participant in the traditional benefit package entitled to a retirement annuity may, prior to retirement, elect to take a reduced retirement annuity and provide with the actuarial value of the reduction, a reversionary annuity to a dependent beneficiary, subject to the following conditions: (1) the participant's written notice of election to provide such annuity is received by the board at least 30 days before the retirement annuity payment period begins, and (2) the amount of the reversionary annuity is not less than $10 per month, and (3) the reversionary annuity is payable only if the participant dies after retirement.
The participant may revoke the election by filing a written notice of revocation with the board. The beneficiary's death prior to retirement of the participant shall constitute a revocation of the election.
The amount of the reversionary annuity shall be that specified in the participant's notice of election, but not more than the amount which when added to the survivors annuity payable to the dependent beneficiary, would equal the participant's reduced retirement annuity. The participant shall specify in the notice of election whether the full retirement annuity is to be resumed or the reduced retirement annuity is to be continued, in the event the beneficiary predeceases the annuitant.
The reversionary annuity payment period shall begin on the day following the annuitant's death. A reversionary annuity shall not be payable if the beneficiary predeceases the annuitant.
40 ILCS 5/15-140