Change column names in search visualize on kibana dashboard

I have create search from discover tab and added to dashboard. I have selected fields I want to show data. Fields names are as per logstash but I want to change those on dashboard. I have tried from saved objects but then values are not showing in search.

i want that column name as Query Class.
I am using oss version 7.4 . First of all is it possible to change or I am expecting more from this version.

7.4 is indeed an old version but you can create an scripted field with the name you want and just output the original field so for the flights sample dataset you can create a new scripted field Destination_Airport with the script:

doc['DestAirportID'].value

And later in Discover you'll have this new field available

This is much better addressed in recent versions of Kibana. So for 7.17 you can just change the label of a field

And this label will be honored in any Kibana application, not only Discover but also Maps, Lens, etc.