You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Can you aid me to book a flight ticket from PHL to SFO?

ASSISTANT: Sure, can you please mention your depart and arrival dates of your journey?

USER: My trip dates are Jan 19 and Jan 21.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight.

ASSISTANT: On what name, do I need to reserve the ticket?

USER: Barbara Wilson here.

ASSISTANT: Sorry, no flights are available as per your requirements.

USER: Thank you.

ASSISTANT: Thank you for reaching us.