You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Can you please  book  a flight ticket from AUS to DEN?

ASSISTANT: Sure, may I know your travel dates?

USER: Thank you. I have planned my travel  dates as Apr 26 and Apr 28.

ASSISTANT: Do you have any specifications?

USER: I would  like to depart in afternoon time so  please make sure  that.

ASSISTANT: Please share me your name.

USER: Sure, myself Dorothy Mitchell.

ASSISTANT: Sorry, there is no flight at this moment.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you.

USER: Most welcome.