You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I planned to meet my friend in IAD, can you please help me to book a flight ticket from AUS?

ASSISTANT: Sure, may I know your travelling dates?

USER: I prefer to travel on Aug 5 and Aug 7.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I prefer to travel in a connecting flight.

ASSISTANT: Ok, may I know your class preference?

USER: I would like to travel in business class.

ASSISTANT: Ok, could I have your name please?

USER: I am Susan Clark.

ASSISTANT: Sorry, there is no flight with your request.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: You are welcome, have a great day.