How do I change my phone number in WhatsApp?
If you've recently switched phones and cell phone providers, chances are you've had to change your phone number. You're a heavy WhatsApp user and need to get back in the saddle because the honeys overseas can't wait too long to hear from you.
You're going to have to change your phone number within WhatsApp. Lucky for you, it's a quick and easy process. Before thinking of changing numbers, you'll want to backup your WhatsApp chats so that they transfer to your new account.
Full story from the WindowsCentral blog...