Mapping fields as date when index already exists

[Giovanni_Di_Lembo]

Hi all and sorry for my poor english.
I've successfully mapped a field as date (for kibana purpose) before ingestioning one document ,using this:

PUT my-index
{
  "mappings": {
  "properties": {
  "currentDate": {
  "type": "date" ,
  "format": "yyyy-MM-dd HH:mm:ss||yyyy-MM-dd||epoch_millis"
}
}
}
}

I wonder how can I do that when a document is already ingestioned.

[aaron-nimocks]

You can't change a mapping once you have indexed some documents using it. You can only add to the mapping with new fields. But you do have 2 options and the 2nd one is probably the easiest as long as you can ingest that document again easily.

Option 1

1. Create mapping you want
2. Reindex into new index using new mapping
3. Delete old index
4. Reindex back to original index name

Option 2

1. Delete your current index
2. Reingest your data with new mapping

[Giovanni_Di_Lembo]

Why do you not plan to enable a mapping runtime on indexed document (if mapping is compliant )?
This is could be a good enhancement.

Thanks for your response!