I'm trying to figure out if it's possible to update only some fields of a document with dataframe transforms similar to the way the index document update API works (https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-update.html).
I have used an existing transform to create the destination documents and I want to add some fields to the same documents. Is there an option for that? From my attempts it seems that new transforms overwrite the old document.
Thanks in advance