First of all, don’t cancel your FEHB coverage unless you are absolutely certain your alternative coverage – the plan you are keeping instead of FEHB – covers what you think it does and costs what you think it does. (Double check – some retirees drop out because their spouse has coverage from a private sector employer’s health plan but not all private sector employers allow their retirees to continue health coverage into retirement, and some of those who do require retirees to pay higher premiums than active employees pay.)
Annuitants who drop out of FEHB cannot re-enroll in the program except under limited circumstances.
Generally, if you are an active employee and your enrollment terminates (other than for entry into military service), the effective date is the last day of the pay period in which the terminating event occurred. If you cancel your enrollment, the effective date is the last day of the pay period in which your employing office receives your cancellation request.
Withholdings and contributions for the full pay period are required. If your coverage terminates because you are in leave without pay status or you have insufficient pay to make the withholding, and you do not elect other payment options, the effective date is the last day of the pay period that you paid your share of the premiums.
Your coverage continues at no cost for 31 days after your enrollment terminates for any reason except when you voluntarily cancel your enrollment or your plan is discontinued. For retirees, coverage ends in most cases at the start of the following month.