The following guidelines will assist you in removing a Hosted Exchange account from an iPhone or iPad device:
1. Go to Settings on the iPhone or iPad device.
2. Select Mail, Contacts, Calendars. The Accounts screen will open.
3. On the Accounts screen, tap the Exchange Account that will need to be removed.
4. Scroll down to Delete Account. A Delete Account warning window will open.
5. On the Delete Account warning window, select 'Delete from my iPhone'.
6. Once this option has been chosen, wait for the account to be removed from the device. This can take some time to remove, depending on the size of the mailbox.
7. Once the account has been removed, you will be returned to the Mail, Contacts and Calendars settings.