Deactivating iCloud unlock

The only way is to contact the previous owner and ask him to remove the device from his iCloud ID. Everything else is illegal, and will cause damage to the device.

 

Your best protection is to make sure any used iPhones you buy are not iCloud Activation Locked before you make the purchase.

 

Apple will only remove iCloud Activation Lock from a device if you’re the original owner and can prove it to Apple’s satisfaction(original sales receipts in your name, purchased direct from Apple). If you purchased a second hand iPhone that’s iCloud Activation Locked there’s no way to unlock it without the Apple ID and password of the original owner.