You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I want to book a flight ticket from AUS to CLT, can you help me with booking please?

ASSISTANT: May I know your desired travel dates please?

USER: My trip dates are Jan 09 and 11.

ASSISTANT: Do you have any specifications?

USER: I prefer to travel in economy class.

ASSISTANT: May I know your name please?

USER: My name is Patrick Hall.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you for opting us.