You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I'm Nancy Martin, I want to travel from DCA o SEA. Can you book my ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are from 12/22 to 12/24.

ASSISTANT: Sorry, there is no flight found as per your request.

USER: It's ok, thank you.

ASSISTANT: You are welcome.