Any member or any beneficiary who has been or, in the future, may be retired, or receive a pension, retirement allowance or benefit pursuant to the provisions of this act, may, by filing written request with the retirement system, waive payment of a portion of the pension, retirement allowance or benefit to which he may be entitled.
Upon the receipt of such waiver, and until the same is withdrawn, altered or revoked by a subsequent written request, similarly filed, the retirement system shall pay a reduced pension, retirement allowance or benefit, as shall be requested in such waiver. The member or the beneficiary shall not be entitled to a refund, or credit, for such moneys as shall have been waived during the period such waiver had been in effect.