Texas Government Code - GOV'T § 854.004. When Annuity is Payable; Changes Before First Payment

(a) A retiree may change the retiree's choice of retirement annuity payment plans or the designation of beneficiary after the retiree's effective date of retirement by filing written notice with the board of trustees before the later of the date on which the retirement system makes the first payment or the date the first annuity payment becomes due. After the first payment has been made by the retirement system or has become due, a retiree may not change the annuity payment plan selected and may not change the designated beneficiary except under Section 854.006.

(b) For purposes of this section, the term “makes payment” includes the depositing in the mail of a payment or the crediting of an account with payment through electronic funds transfer.

(c) An annuity under this subtitle is payable for a period beginning on the last day of the first month following the month in which retirement occurs and ending, except as otherwise provided by this subtitle, on the last day of the month in which death occurs.