Apple Mail - Removing Saved Passwords

Follow the steps to Change Your Stored Password   

1. Open Mail   
2. Go to the Mail menu and select Preferences   
3. On the left-hand side ensure the account you wish to change is highlighted   
4. On the right-hand side remove any password in the Password field   
5. Close Mail   
6. Reopen mail and you will be prompted for your password   
7. Enter your new password   
8. Check the box "Remember this password in my keychain"

To Remove Your Stored Password

1. Follow steps 1 to 4 listed above   
2. Leave the Password field blank   
3. Close Mail   
4. Reopen mail and you will be prompted for your password