You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I have appointment with my family doctor on 06/01 at Denver, CO - DEN. Can you please book me a flight ticket?

ASSISTANT: Sure, can you please help me with your origin point?

USER: My origin is Austin, TX - AUS.

ASSISTANT: May I know your return journey date?

USER: I need to return on 06/03.

ASSISTANT: Thank you for your details. Sorry, we did not found any flights based on your preferences.

USER: Ok, no issues. Thanks for your kind help.

ASSISTANT: May I know your name please?

USER: Brenda Davis is my name.

ASSISTANT: Thank you for reaching us.