You cannot edit a contact who is added in your personal directory from the System directory, they remain linked to the matching entry on the System directory tab.
1. Search for the contact in the directory.
2.Click 
Update Contact.
a.Type the details of the contact in the Contact Details window.
•If the Work phone setting matches the extension number of a telephone system user, the directory contact displays the user status of the user. This applies even if another number is currently selected as the Primary phone.
•You can select the Group in which of your personal contact should appear on.
•You can add the gmail address of the contact. After you add the addresses you can start an email or initiate a chat from Avaya IP Office Plug-in directory.
b.When finished, click Add.