how do you re-name a device

Change the name of your iPhone, iPad, or iPod touch

To change the name of your iPhone, iPad, or iPod touch, follow these steps:

1. On your device, go to Settings > General, then tap About.
2. Tap the first line, which shows the name of your device.
3. Rename your device, then tap Done.

Change the name of your iPod classic, iPod nano, or iPod shuffle

1. Connect your device to your computer.
2. On a Mac with macOS Catalina 10.15, open Finder. On a Mac with macOS Mojave 10.14 or earlier, or on a PC, open iTunes.
3. Locate your device on your computer.
4. Click the name of your device near the top-left.
5. Enter the new name for your device, then press Return.

https://support.apple.com/en-us/HT201997#:~:text=On%20a%20Mac%20with%20macOS%20Mojave%2010.14%20or%20earlier%2C%20or,your%20device%2C%20then%20press%20Return.

To change the name of your iPhone, iPad, or iPod touch, follow these steps: On your iOS device, go to Settings > General > About. Tap the first line, which shows the name of your device. Rename your device, then tap Done.

From: Change the name of your iPhone, iPad, or iPod - https://support.apple.com/HT201997

On a Mac: Apple menu > System Preferences > Sharing > Computer Name.

On an iPhone or iPad: Settings > General > About > Name