Aruba provides you with a Control Panel so you can manage your email accounts as and when you like.

In fact, from the Email Account Management menu you can create, edit or delete accounts, aliases, autoresponders and Mailing Lists. 

To manage the domain email accounts, you need to access the Aruba Webmail using the username and password of the Postmaster account.

Once you have logged in you will find the Management - Email Account Management menu, which includes various options for managing the domain email accounts.