POST /

Content-Type: application/x-www-form-urlencoded

Action=ModifyTransitGatewayMeteringPolicy&AddMiddleboxAttachmentId.1=__Member__&AddMiddleboxAttachmentId.2=__Member__&DryRun=true&RemoveMiddleboxAttachmentId.1=__Member__&RemoveMiddleboxAttachmentId.2=__Member__&TransitGatewayMeteringPolicyId=__TransitGatewayMeteringPolicyId__&Version=2016-11-15