Change the database files? Do you mean modify the orm?
I think the user search uses that, can't remember, maybe take screenshots of what you're looking at and say how you'd need it, then we could help with changing it.
FYI: advanced search is for finding tickets, not users. You can arrange your users into organisations or simply use the users tab to see all tickets for a user, but I've not tried to search for a user without having a ticket open that needed dealing with.
Call management? Do you mean phone calls? Maybe you'd need a CRM tool rather than a ticketing system?
Which bank is getting development done by an intern? Are they paying you? I have many questions apparently.