1. Press Start, then swipe left to the App list.
  2. Tap Settings and then tap email+accounts.
  3. Tap and hold on the account you want remove and select delete. If this fails, switch your phone to flight mode and reboot. At this point you should delete your account.
  • Important: If you want to change your Microsoft (Windows Live) account you use on your phone, you must first reset your phone to factory settings: Select Settings > about > reset your phone and then confirm the option warns about data loss.