Elastic sink data for new index with ingest pipeline

Elastic Stack Elasticsearch
1

Dear Team,

We are having data coming from the elastic sink
kafka topics >>elastic Sink >> Elastic Search

When we get data to Elasticsearch, there are some fields in which we want to transform data.
Example :
LastModifedDate : "yyyy-MM-dd HH:mm:ss.SSSXXX" - 2001-07-04 12:08:56.235-07:00
CreatedDate : "yyyy-MM-dd'T'HH:mm:ss.SSSXXX" - 2001-07-04T12:08:56.235-07:00

Note: Both values are coming as String.
The required format is DD MM, YYYY HH:mm:ss.SSS

So, we are using ingest pipeline to convert this data and set this as default pipeline for an index (for indexed index).
Now, the challenge here is that we want the live data that is getting into old index need to be in new index with transformed values. Is it possible, If possible how to do that.
Kindly provide me with sufficient details.

Thanks and Regards,
Pavan Satya.