The young lady should go to the Los Angeles regional passport office with:

1 Her filled-in application but not signed. (She can fill it in on line, then print it out.)
2 Two passport photos (go to the Auto Club, FedExKinkos or any of numerous passport photo places in town)
3 Her birth certificate or naturalization certificate. (Proof of citizenship)
4 Her Photo ID, usually a drivers license (Proof of ID)
5 Her checkbook or greenback cash for the application fee and expediting fee

6 AND, since she wants the passport overnight, she should present evidence of immediate travel needs, including airline tickets or proof of close relative with grave illness, etc.

Depending on the urgency of the matter, the LA passport office can make the passport on the spot or send it in for expedited treatment. They can issue a passport immediately for truly life or death situations. I personally know of a heart surgeon who got a passport in the Los Angeles office, then was on a plane headed to the patient's location within a few hours.

Most of the time, however, the turnaround time involves sending everything to the National Passport Issuance Center, then getting it from them.