Changing an existing account
Using the default Mail app
1. Tap Settings > Mail, Contacts, Calendars >Accounts > Tap on the account to be edited.
2. Tap on the email address beside Account
3. You can now change incoming server details and and login information.
Note: The app may autofill your settings. If it doesn't use these settings:
User Name: Type your email address, for example email@example.com
6. To change outgoing server setting tap on the SMTP section.
7. You can now enter the outgoing mail settings
Outgoing Mail Server
Password: Type your password.
8. You should now be able to save and test the connection.