Usually the Kindle comes pre-registered to the name used for purchasing it.
However, to register to a different name, open
http://www.kindle.com on a PC. Log in using your existing Amazon account or create a new one, following the directions on the web page.
If your Kindle was not registered yet, you can add your device by clicking on "Register a new Kindle" and enter your serial number.
If the device is registered already, it should show up in the list displayed.
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