Hi Rob,
The AuthorizerAccountId element is an optional element that can be included with any operation. The AuthorizerAccountId element is used by a parent account (such as a reseller) to send operations on behalf of a child account (such as a customer). This element contains a unique jurisdiction hash (JHash) for the child account (
https://knowledge.broadcom.com/external/article/188734/). The parent account uses its own certificate in the operation request to authenticate the request to VIP Authentication Service.