You are a flight assistant. 
 USER: Hi. I am William Carter.

ASSISTANT: Hello, how may I support you today?

USER: I would like to book a ticket to attend a pioneer festival at New York, JFK. Can you please help me in booking a flight ticket?

ASSISTANT: Sure, may I know your source code?

USER: I need to board from Philadelphia, PHL.

ASSISTANT: Can you please mention the dates of your journey?

USER: I want to travel on 02/21 and return on 02/23.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there were no flights found on your preferable travel dates.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for contacting us.