public void setExistingPolicyId(String existingPolicyId) {
        this.existingPolicyId = existingPolicyId;
    }
<p>
If the recommended action for the unused permissions finding is to detach a policy, the ID of an existing policy
to be detached.
</p>

@param existingPolicyId
       If the recommended action for the unused permissions finding is to detach a policy, the ID of an existing
       policy to be detached.
aws-java-sdk-accessanalyzer/src/main/java/com/amazonaws/services/accessanalyzer/model/UnusedPermissionsRecommendedStep.java