You can change the domain name of your Managed WordPress account.

Log in to your TsoHost Client Area account.

Navigate to Services -> My Services -> select the Managed WordPress service -> click on Login to Server

From the Dashboard navigate to Settings -> click on Add next to Domains from the drop-down menu select New additional doman.

Finally from the dots next to the domain select Make primary domain.

Note: It can take up to 24-48 hours for any DNS changes to take effect.