In order to edit an MX record of a domain on your dedicated server, follow these steps:
- Log in your WHM control panel.
- Click on the DNS Functions link and then on the next page follow the Edit MX Entry link.
- Find the domain that you want to edit and click Edit.
- Modify the MX records and when you are ready, click Save.
After that you may have to allow up to 48 hours for the changes to take effect.