You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: I want to visit The Willis Tower in Chicago, IL - ORD. Can you please help me in booking tickets?

ASSISTANT: Sure, May I know the source code?

USER: I will take off from Houston, TX - IAH.

ASSISTANT: Please help me with your travel dates.

USER: I will travel from 09/22 to 09/24.

ASSISTANT: May I know your name?

USER: Sure, my name is Sharon Thompson.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: No problem at all. Thank you.

ASSISTANT: Thank you for reaching us.