You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you at this moment?

USER: As I am a doctor, can you please book a flight ticket to Austin to attend a surgery?

ASSISTANT: Sure, I will help you with that. Can you please mention your preferable travel dates?

USER: My journey dates are, depart on Sep 26th, and arrival on Sep 28th.

ASSISTANT: May I know your preferable airport code names?

USER: My airport codes are, LAS to AUS.

ASSISTANT: May I know your name for further process?

USER: My name is Donna Collins.

ASSISTANT: Is there any additional preferences do you have?

USER: I need a connecting flight. And I prefer business class.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.