Create a mapping for an unmapped field in a data

Dear Team,

We are having a APM integration in our Elasticsearch instance, where we are having some of the unmapped fields as highlighted in the above Screenshot (please consider the field names which are highlighted).
We need that fields to be searchable in order to make them mapped fields is it possible to do that with out reindexing the index.

Kindly need your support on this.

Thanks and Regards,
Pavan Satya.