postInsuranceDeleteMemberPlans(insuranceDeleteMemberPlansInputRepresentation, memberId)

// Delete Member Plan(s) for a Group Census Member via Connect API (simple version)

// 1) Create the top-level input
ConnectApi.InsuranceDeleteMemberPlansInputRepresentation input = new ConnectApi.InsuranceDeleteMemberPlansInputRepresentation();
// 2) Provide the list of existing Group Census Member Plan record Ids to delete
//    Uses a simple string list wrapper
List<String> planIdsToDelete = new List<String>{
    '0rgxx000000003LAAQ',
    '0rgxx000000003UAAQ'
};
input.plans = planIdsToDelete;
// 3) Execute the POST Delete Member Plans API
//  URL param is the Group Census Member Id whose plans you want to delete
String memberId = '0r6xx00000004LGAAY';
try {
    ConnectApi.InsuranceDeleteMemberPlansOutputRepresentation result =
        ConnectApi.InsuranceGroupBenefitsFamily.postInsuranceDeleteMemberPlans(input, memberId);
    System.debug('Delete Member Plans result: ' + JSON.serializePretty(result));
} catch (Exception e) {
    System.debug('Error while deleting member plans: ' + e.getMessage());
}