You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I need your help to book a ticket from IAD to DCA.

ASSISTANT: Can I know your journey dates?

USER: My departure date is 11/26 and return date is 11/28.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Can I know your name please?

USER: My name is Emma Campbell.

ASSISTANT: Sorry Emma, I didn't find any flight regarding your details.

USER: That's really sad. Anyways, thank you for the information.

ASSISTANT: Your welcome.