You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How may I assist you today?

USER: Please book a ticket from Chicago, IL-ORD to Dallas & Fort Worth, TX-DFW.

ASSISTANT: Sure, may I know your travel dates to search best flight for you?

USER: Departure date is 09/12 and 09/14 is return date.

ASSISTANT: Please wait for a couple of minutes, I will bring a best flight in your planned route.

USER: Sure.

ASSISTANT: May I know your name for documentation purpose?

USER: I am Dorothy Brown.

ASSISTANT: Sorry, I could not find any flight with your travel dates.

USER: Thank you.

ASSISTANT: You are welcome.