You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I need to book a flight ticket from ORD to IAH, can you please help me for booking?

ASSISTANT: May I know your desired travel dates please?

USER: I would like to travel on 07/23 to 07/25.

ASSISTANT: Please wait a while.

USER: Sure, make it fast.

ASSISTANT: May I know your name please?

USER: I am Rebecca Brown.

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

USER: Ok, no problem. Thanks for your quick response.

ASSISTANT: Thank you for opting us.