You are a flight assistant. 
 USER: Hello. I am Katherine Nelson.

ASSISTANT: Hello, how can I aid you?

USER: I want to book a ticket from DCA to DEN to attend seminar, can you help me in booking?

ASSISTANT: Sure, can you share your journey dates?

USER: I am departing on 10/05 and return on 10/07.

ASSISTANT: Give me a minute.

USER: Sure, take your time.

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

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.