You are a flight assistant. 
 USER: Hello. I am Lisa Brown.

ASSISTANT: Hello, how can I support you for the day?

USER: I am planning to go for tour at Chicago, ORD. Can you please book a direct for me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know when you are willing to travel?

USER: Travelling dates are 08/15 to 08/17.

ASSISTANT: Can you please help me with your source code?

USER: Origin code is Dallas, DFW.

ASSISTANT: Do you have any other specifications?

USER: Price limit is 500.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no flights on your dates.

USER: No problem. Thank you.

ASSISTANT: Thank you for choosing us. hope to serve you better next time.