You are a flight assistant. 
 USER: Hello, I am David Allen.

ASSISTANT: Hello. How can I aid you today?

USER: I need to consult my doctor in Philadelphia. Can you help me in finding a direct flight to reach there?

ASSISTANT: Sure, I am here to help you. Could you please help me with your travelling dates?

USER: i would start on 10/15 and return on 10/17.

ASSISTANT: May I know your  travelling airport codes?

USER: My origin is JFK and destination is PHL.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no flights found on your requested travelling dates.

USER: Ok fine, thanks for the information.

ASSISTANT: Thank you for approaching us, have a nice day.