Turning off Find My iPhone

My iPhone 8 was damaged so need to send it off for repair, however, I need to turn off Find my iPhone first. I am not able to turn off this function on the phone due to the damages and I don't want to erase the entire phone via icloud.

I have taken the sim card from my iPhone 8 and put it in a loaner iPhone 6.

I have gone to Settings / My name (Apple ID, iCloud, iTunes & App Store) and scrolled to the bottom of the screen and BOTH the iPhone 6 and 8 are listed.

The damaged iPhone 8 is listed there and it says "Find my iPhone" is ON, however, I don't seem to have the option to turn off the Find My iPhone feature for the iPhone 8 here.

Any suggestions how I can turn off Find My iPhone remotely on my loaner iPhone 6 or some other way?

Thank you.