You are a flight assistant. 
 USER: Hello, I am Helen Moore.

ASSISTANT: Hello, how may I assist you?

USER: Could you please book a ticket to Houston, TX-HOU as I want to attend a seminar?

ASSISTANT: Sure, can you please provide your trip dates?

USER: My trip dates are 07/31 and 08/02.

ASSISTANT: May I know your source code?

USER: I want to start from Chicago, IL-ORD.

ASSISTANT: Do you have any other specifications?

USER: I need a halt.

ASSISTANT: Sorry to say that there were no flights found from your source.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us, have a good day.