how to transfer text messages and call logs - 6s to a 6s without losing history on the phone receiving the messages

[CloudStrategist]

I have a brand new 6s that suddenly died on me. I had been using this for just over 2 weeks.

Verizon sent me a replacement phone and a week later the new phone turned itself back on and now works.

The genius bar at Apple conducted a diagnostic check and believes the original phone is okay - felt is was an ios upgrade issue and resolved once I downloaded the new version.

Question:
I have text messages and call logs on both phones. How to I move over those messages from the replacement phone to my original without losing the ones on my original device - (I AM LOOKING TO MERGE THE DATA WITHOUT SACRIFICING DATA ON 1 Phone for the other).

Not yet found any way to do this .... itunes or icloud only allows a 1 way transfer that replaces anything on the receiving device.

Kathleen