Hello Vollaw522,
If you are using your iPhone, Power cycle the iPhone using these instructions: Restart your iPhone - Apple Support While simple, this can refresh the iOS, apps and connections.
After restarting, try and rename the AirTag using these steps found here: Set up your AirTag using your iPhone, iPad, or iPod touch - Apple Support:
1. Open the Find My app, then tap the Items tab.
2. Tap the AirTag whose name or emoji you want to change.
3. Scroll down and tap Rename Item.
4. Select a name from the list or select Custom Name.
5. Type a custom name for your AirTag and select an emoji.
6. Tap Done.
If you are still not able to complete the name change, do you have any other Apple devices you can use to try and work through the steps?
Cheers.