How can I writeback data through Slate using Table Storage Service?

I am trying to update a value in a writeback dataset and want to use Slate/phonograph2 and the Table Storage Service-endpoint: Post Event. But I receive the below error: “errorCode”: “INVALID_ARGUMENT”,“errorName”:“Phonograph2:ReadOnlyTables”

This endpoint can only be used to update tables with a writeback dataset and not to update the writeback dataset directly:

If you send an update via this endpoint to a dataset, it will update (only) the corresponding writeback dataset.

Example: datasetA(ri.phonograph2.main.table.1234) has writeback dataset datasetB(ri.phonograph2.main.table.5678). You want to update a value datasetB with the Table Storage Service and Post Event-endpoint. Your query parameters would be: tableRid: ri.phonograph2.main.table.5678 tableEditedEventPostRequest:

{
  “primaryKey” : {
    “id” : “abc”
  }, 
  “payload” : { 
    “type”:”rowModified“,
    “rowModified”: {
      “columns”: {......}
    }
  }
}