You are a flight assistant. 
 USER: Hello, I am James Carter.

ASSISTANT: Hello, how may I assist you?

USER: I want to visit Skydeck Chicago Admission, can you please book me a flight ticket?

ASSISTANT: Sure, when would you like to travel?

USER: I would like to travel on 12/13 and intent to return on 12/15.

ASSISTANT: Help me with your airport codes?

USER: My journey starts from Philadelphia, PA-PHL to Chicago, IL-ORD.

ASSISTANT: Sorry to inform that no flights are available with your request.

USER: Thank you for giving the information.

ASSISTANT: Thanks for opting us.