You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to travel to Chicago to visit Cloud Gate. Can you help me in booking a ticket?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: Well, they are PHL and ORD respectively.

ASSISTANT: Can you please provide your travel dates?

USER: I am planning my journey on 05/21 and return 05/23.

ASSISTANT: Please provide your name for further proceedings.

USER: My name is Alexander Green.

ASSISTANT: Sorry Green, no flights have been found on your requested dates.

USER: That's fine, thank you for the information.

ASSISTANT: Thank you for choosing us.