We have a module under the title "Advocates" which uses the Advocate's first name as the required primary key. I would like to add the Advocate's last name in their title as well. 

Under the "Summary" of the Module where I go to customize the page, it says "CustomModule2" next to "Module" and "API Name" (please refer to image attached).

How can I add the Advocate's last name as part of the primary key? It does not allow me to edit that field, even though I can edit the "Displayed as:" key. In addition, the "Module Permission" is set for "Administrator, Standard" (see attached image). 

Please let me know what I can do in situation. 

Thank you!