There are two possible ways, as of current versions, to determine the purpose: (RECOMMENDED) Align your purpose with the HTTP verbs used in RESTful API transactions. Use a POST verb to create a BOL request, use a PUT verb to update a BOL request, and use a DELETE verb to cancel/delete a BOL request. Use a single POST call and describe intent in the "function" variable. Valid values are CREATE, UPDATE, and DELETE; however this use is discouraged in favor of RESTful API best practices.