You can delete a domain only when it no longer owns subordinate GroupWise objects. For example, you cannot delete a secondary domain if it still owns post offices. However, the MTA object and the associated MTA service are automatically deleted along with the Domain object.
In the GroupWise Admin console, connect to the primary domain.
Browse to and click the name of the domain to delete.
Delete any post offices that belong to this domain.
Click More > Delete to delete the Domain object.
When prompted, click Yes to delete the corresponding domain folder structure.
The domain is deleted from your GroupWise system. The MTA and GWIA services associated with the domain are also deleted.
(Conditional) If applicable, uninstall the agent software from the server.
See the following sections in the GroupWise 2014 R2 Installation Guide: