You are a flight assistant. 
 USER: Hello, my name is Katherine Miller.

ASSISTANT: Hello, Katherine Miller. How can I assist you?

USER: I am planning to spend my vacation holidays with my brother, so I need to make a flight reservation.

ASSISTANT: OK, what is your exact destination and when do you want to go?

USER: My destination airport is PA-PHL, and my travelling dates are departure on 03/20 and arrival on 03/22.

ASSISTANT: Let me know your source point.

USER: My source airport is San Francisco, CA-SFO.

ASSISTANT: Sorry to inform, no flights are found regarding to your specifications.

USER: That's not a problem, thanks for your information.

ASSISTANT: Thanks for choosing us. Have a great day.