Web API - Updating Sets
If no records are specified in the set then nothing will be updated. To update a record use "action" : "update". To remove a record use "action" : "remove". To add a record use "action" : "add". Different actions can be used within the same set. For example:
"set": [ { "action": "update", ........... }, { "action": "remove", ........... }, { "action": "add", ........... } ]