1. From the device home screen, tap the Apps button in the lower right corner.
2. Tap the Settings app.
3. Tap User and Backup settings.
4. Tap Accounts.
5. Tap the existing Microsoft Exchange ActiveSync account.
6. Tap the account Settings.
7. Tap the menu button in the top right corner.
8. Tap Remove account and acknowledge the confirmation request to remove the account from the device.