You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: Sure. May I know your name please?

USER: My name is Thomas Young.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: I found your flight reservation. Tell me your airport codes please?

USER: My source code is DFW and destination airport code is AUS.

ASSISTANT: Tell me your travel dates please?

USER: I am planning to travel on Jan 24 and return back on Jan 26.

ASSISTANT: May I know your name please?

USER: My name is Thomas Young.

ASSISTANT: Are you looking for a stopover in your journey?

USER: I am looking for a direct flight.

ASSISTANT: Any other preferences?

USER: No.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry there are no direct flights available.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you.