the member may elect to change the member's designated beneficiary or form of benefit under subsection (b) and to receive an actuarially adjusted and recalculated benefit for the remainder of the member's life or for the remainder of the member's life and the life of the newly designated beneficiary. The member may not elect to change to a five (5) year guaranteed form of benefit. If the member's new election is the joint and survivor option, the member shall indicate whether the designated beneficiary's benefit shall equal, at the option of the member, either the member's full recalculated retirement benefit or two-thirds (2/3) or one-half (1/2) of this benefit. The cost of recalculating the benefit shall be borne by the member and shall be included in the actuarial adjustment.
after the first day of the month in which benefit payments are scheduled to begin. For purposes of this subsection, it is immaterial whether a benefit check has been sent, received, or negotiated.
IC 5-10.2-4-7