You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am Cynthia Jones. Can you please book a ticket from IAH to DCA?

ASSISTANT: Sure, I will help you. May I know your travel dates?

USER: My journey dates are Nov 18 and Nov 20.

ASSISTANT: Ok, please wait. Let me check for the available flights.

USER: Ok.

ASSISTANT: Sorry, there is no flight available on your given travel dates.

USER: Ok, no worries. Thank you.

ASSISTANT: You are welcome and thank you for choosing us.