改計劃或者再加入某項計劃,保險公司就可以要求退休人員提供健康證明,或者可以拒絕或者要求支付更高的保險費。
有些州有例外。
https://www.medicaresupplement.com/enrollment/can-i-change-my-medicare-supplement-plan/#:~:text=Yes%2C%20you%20can%20change%20your,for%20pre%2Dexisting%20health%20problems.