You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Can you please book a ticket from PA-PHL to NY-JFK?

ASSISTANT: Yes, can you please provide the departure and arrival dates?

USER: The departure date is 07/13 and the arrival date is 07/15.

ASSISTANT: OK. Sorry to inform you that no flights are available on your requested dates. May I know your name for documentation purpose?

USER:  It's OK. Sure, I'am William Moore.

ASSISTANT: OK, thank you.

USER: Thank you for your help.