personal and primary iPhone message issue

You do not need to sign out of your Apple ID to change the label of your SIM from "Primary" to a customized label.

The process can be done directly on your iPhone by following these steps:

1. Open the Settings app on your iPhone.
2. Tap on Cellular (or Mobile Data, depending on your region).
3. Select the line you want to rename (e.g., Primary, Secondary, or a previously set label).
4. Tap on Label or Cellular Plan Label.
5. Choose a predefined label (e.g., Business, Personal, etc.) or create a custom label.
6. Once you've made the change, it will automatically update without requiring you to sign out of your Apple ID.

This applies as long as the SIM or eSIM is already activated on the device.