You can unlink your Kindle from your account by going to Settings and then Manage Your Devices. Select the device you want to unlink, and then select Unlink this Device.
No, one Kindle can only be registered to one account.
KDP stands for Kindle Direct Publishing, a platform for publishing eBooks.
If you are using the Kindle app on your iPhone, you can go to Settings -> My Devices and click on “Kindle”.If you are using the Kindle app on your Android device, you can go to Settings -> My Devices and click on “Kindle”.If you are reading this answer on a Kindle device, then tap the Menu icon in the top-left corner of the screen. Tap Settings -> My Account.
