Merge 2 indexes live

Hi
I have 2 indexes with following names
Cloudfront
cfID
Status
Domain and ....
ExtraLoggingCloudfront
cfID
extraHeaderCheck1
extraHeaderCheck2

In the 2 indexes i have different fields but there is 1 field which is same cfID

I want to merge this to indexes and add that 2 - "extraHeaderCheck1" and "extraHeaderCheck2" to cloudfront logs how i should do this what are the options