You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am looking for a flight from DEN to SEA, can you help me in booking?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, my planned travel dates are Apr 25 and Apr 27.

ASSISTANT: Do you have any class or time preferences?

USER: I need a flight in an economy class.

ASSISTANT: May I know your name?

USER: Myself Brenda Turner.

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

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: You are welcome, have a nice day.