10 U.S.C. § 1436

(a) The reduction in the retired or retainer pay of any person who elects an annuity under this subchapter shall be computed by the armed force concerned as of the date when the person becomes eligible for that pay but without regard to any increase in that pay to reflect changes in the Consumer Price Index. It shall be computed under an actuarial equivalent method based on (1) appropriate actuarial tables selected by the Board of Actuaries, and (2) an interest rate of 3 percent a year, or such other rate as the Secretary of the Treasury, after considering the average yield on outstanding marketable long-term obligations of the United States during the preceding six months, may specify by August 1 of any year for the following year. The method and tables shall be those in effect on the date as of which the computation is made. (b) Under regulations prescribed under section 1444(a) of this title , the Secretary concerned may, upon application by the retired member, allow the member— (1) to reduce the amount of the annuity specified by him under section 1434(a) and 1434(b) of this title but to not less than the prescribed minimum; or (2) to withdraw from participation in an annuity program under this title; or (3) to elect the annuity provided under clause (1) of section 1434(a) of this title in place of the annuity provided under clause (3) of such section, if on the first day for which retired or retainer pay is granted the member had in effect a valid election under clause (3) of such section, and he does not have a child beneficiary who would be eligible for the annuity provided under clause (3) of such section. For this purpose, a child (other than a child who is incapable of supporting himself because of a mental defect or physical incapacity existing before his eighteenth birthday) who is at least eighteen, but under twenty-three years of age shall not be considered an eligible beneficiary; or (4) to elect that a child (other than a child who is incapable of supporting himself because of a mental defect or physical incapacity existing before his eighteenth birthday) who is at least eighteen, but under twenty-three years of age shall not be considered eligible for the annuity provided under clause (2) of section 1434(a) of this title , or for an annuity provided under section 1434(b) of this title , if on the first day for which retired or retainer pay is granted the member had in effect a valid election under clause (2) of section 1434(a) of this title , or under section 1434(b) of this title . A retired member may not reduce an annuity under clause (1) of this subsection, or withdraw under clause (2) of this subsection, earlier than the first day of the seventh calendar month beginning after he applies for reduction or withdrawal. A change of election under clause (3) of this subsection shall be effective on the first day of the month following the month in which application is made. An election under clause (4) of this subsection shall be effective on the first day of the month following the month in which application is made and, if on the effective date there is no surviving child who would be eligible for an annuity provided under clause (2) of section 1434(a), or under section 1434(b), of this title if the elector died, no deduction shall be made for such an annuity to, or on behalf of, a child from the elector’s retired or retainer pay for that month or any subsequent month. No amounts by which a member’s retired or retainer pay is reduced prior to the effective date of a reduction of annuity, withdrawal, change of election, or election under this subsection may be refunded to, or credited on behalf of, the member by virtue of an application made by him under this subsection.