Email aliases provide alternative email addresses for a member's mailbox. For example, email aliases for a member named "Sample Member" could look similar to the following:
sample_member@mydomain.com
smember@mydomain.com
sample@mydomain.com
Email sent to any one of these addresses would arrive at Sample Member's mailbox.
To assign email aliases for a member:
In the Menu, click WebEx Mail > Administration.
Click the Mailboxes link. The Mailboxes list appears.
Click the edit icon 
next to the
mailbox you want to edit. The Edit Mailbox page for the mailbox you selected
appears.
Edit the alias list in the Email Aliases box. Separate aliases with a comma and do not include your WebEx mail domain. For example:
smember, sample.member, sample
Click Save