A Google Apps user has two names: a display name consisting of a first name and last name, and a user name that appears before the @ sign in his or her primary email address. You can change either or both of these names. You can't change your own user name.

The effect of changing a user's display name depends on whether the user has Google+. If the user has a Google+ profile, Google products such as Gmail show his or her profile name and the display name from the Admin console appears only in the Admin console. If the user does not have a Google+ profile, Google products show the user's display name from the Admin console.

To rename a user:

1. Have the user log out of his or her Google account.
    
2. Sign in to the Google Admin console. 
    
3. Click Users. 
    
4. If you created an organizational structure, select the organizational unit to which the user belongs.
    
5. Select the check box next to the user's name and select More actions > Rename user, or click the row to open the user information page for that user and click the Rename user link.
    
6. Enter the new name for the user.
   
   You can change the user's display name (First name and Last name) as well as his or her Primary email address. If your Google Apps account includes multiple domains, you can change the domain name by selecting it from the drop-down list.
    
7. Click Rename user.
   
   It can take up to 10 minutes for a new primary email address to be reflected throughout the system, 24 hours for domain and personal contact changes to take effect, and up to 3 days before the user can use Google Talk. See Impact of renaming a user for a complete description.