38 CFR § 9.3 - Waiver or reduction of coverage.
(a) Full-time coverage which is in effect will terminate or be reduced at midnight of the last day of the month a member's written notice requesting such termination or reduction is received by his or her uniformed service. In the case of a member paying premiums directly to the administrative office, full-time coverage will terminate or be reduced as of the last day of the month for which the last full premium was paid. Termination or reduction of coverage is effective for the entire remaining period of active duty unless the member reinstates his or her coverage under the provisions of 38 U.S.C. 1967(c). If, following termination of duty, a member reenters duty (in the same or another uniformed service), a waiver or reduction for the previous period of duty will not apply to the subsequent period of duty.
(b) Part-time coverage will terminate or be reduced at the end of the last day of the period of duty then being performed if the member is on active duty or active duty for training when the waiver or reduction is filed; at the end of the period of inactive duty training then being performed if the member is on inactive duty training when the waiver or reduction is filed; or on the date the waiver or reduction is received by his or her uniformed service if the member is not on active duty, active duty for training; or inactive duty training on the date the waiver or reduction is filed.
(1) When a member insured under part-time coverage waives his or her right to group coverage or elects a reduced amount of insurance, such waiver or election, unless changed, is effective throughout the period of the member's continuous reserve obligation in the same uniformed service. If, following termination of duty, the member reenters duty or resumes the obligation to perform duty (in the same or another uniformed service), the waiver or reduction will not apply to the subsequent period of duty or obligation.
(2) If a reservist insured under part-time coverage is called or ordered to active duty or active duty for training under a call or order that does not specify a period of less than 31 days and is separated or released from such duty and then resumes his or her reserve obligation, any waiver or election of reduced coverage made while eligible for part-time coverage, unless changed, shall be effective throughout the entire period of part-time coverage, the active duty or active duty for training period and 120 days thereafter and the period of immediately resumed reserve obligation.
(3) If a member, other than a member referred to in paragraph (b)(2) of this section, upon termination of duty qualifying him or her for full-time coverage assumes an obligation to perform duty as a reservist, any waiver or election previously made by the member shall not apply to coverage arising from his or her reservist obligation. Furthermore, during the 120 days following termination of such duty the full-time coverage shall not be reduced by any waiver or election made by a member as a reservist.