You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Gregory Lopez.

ASSISTANT: How may I help you?

USER: I'm planning to attend convocation meeting at Austin, can you please help me with booking a flight ticket?

ASSISTANT: Sure, I will help you out. Can you please provide your preferable dates of travelling?

USER: Sure, I would like to take off on 12/22 and return back on 12/24.

ASSISTANT: Ok, may I know your origin and destination airport codes for booking?

USER: My source airport code is IAD and the destination airport code is AUS.

ASSISTANT: Please wait a moment to check the flights.

USER: Ok, but please make sure that the connection is 0.

ASSISTANT: Sorry to inform you that, there are no flights available for your request.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for reaching us, have a great day.

USER: You are welcome.