In Exchange, you might have a number of accepted domains and manually editing the information can be a daunting task. The PowerShell script below updates the Name value with the new name. If you use a 3rd party provider like Ensim, they generally add a bracket () with a number behind the name and this can cause issues if you shift providers and it cannot verify the domain name. Here is the script link:
The CSV file contains 4 columns: Domain, DomainName, DomainType and Default
The above will import a PSSession if you have not run this from an Exchange server. The next step will look at the CSV file and map out the fields and lastly set it to the Domain name which should be the correct one.
PowerShell to the rescue especially when having to update thousands of records.
Hope it helps.