iOS 18 introduces the ability to give Siri a different name

Apple added the Vocal Shortcuts feature to iOS 18 - special voice commands to trigger certain actions. But when iOS 18 became available in beta, users discovered that Vocal Shortcuts allows you to rename Siri.

Here's How It Works

To set up a voice command for Siri, open the Settings app, go to "Special Features" and scroll down to "Voice Commands." From there, select "Customise voice commands" and choose "Siri". Next, enter any new name - and use it.

So, in the future, you will no longer have to say "Hey Siri" to launch the voice assistant - you can simply voice the new name.
In the meantime, Siri will still be activated using the standard "Hey Siri" phrase as well as a shortcut.

Note that this only works on iPhones - the new Siri name won't work on other devices.

Source: Macrumors