You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I am Joseph Martin. I have planned to visit Central Park with my family on 12/09, can you book me a flight ticket?

ASSISTANT: Sure, May I know the journey codes?

USER: Sure, I am going from PHL to EWR.

ASSISTANT: Please help me with your return date.

USER: I would like to back on 12/11.

ASSISTANT: Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates. Thank you for opting us.

USER: Ok, I will search another agency then. Thank you.