Transfer data from old iPhone to new one

You'll have to restore it to factory condition in order to do that again. It's basically just restarting the entire process.

Use iCloud to transfer data from your previous iOS or iPadOS device to your new iPhone, iPad, or iPod touch - Apple Support

1. Turn on your new device. A "Hello" screen should appear. If you've already set up your new device, you need to erase it before you can use these steps.*