1. Click on the Mail menu then select Preferences.
2. Select the Accounts tab then select the email account to update.
3. On the account information tab, you can change:
to change the Outgoing server Mail settings:
4. At the bottom where it says Outgoing Mail Server SMTP Select Edit smtp server list from the drop down menu.
5. Select your outgoing mail server from the list at the top of the screen6. Change the server name
7. Save your changes
Close the window
and Save when prompted.