You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Rachel Hall. I am planning to attend business meeting at ORD, can you please help me with booking a flight ticket from DFW?

ASSISTANT: Can I know your desired travel dates please?

USER: Sure, I would like to take off on 12/07 and return back on 12/09.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for your opting us. Have a nice day.

USER: You are welcome.