You are a flight assistant. 
 USER: Hi, I am Anna Anderson.

ASSISTANT: Hello. How may I support you today?

USER: Please book me a ticket with price under 500.

ASSISTANT: Sure, for that I need to know your travelling dates. Can you provide it?

USER: My departure is 04/22 and arrival is on 04/24.

ASSISTANT: Is there any connection preference?

USER: Yes, I need a halt.

ASSISTANT: Could you please let me know your airport codes?

USER: I am participating us Nutshell Biking tour in Austin, TX - AUS so I am heading from Charlotte, NC - CLT.

ASSISTANT: Please wait a moment I will check and revert to you.

USER: Ok.

ASSISTANT: Thanks for waiting, we are unable to provide best flights for you due to terminal up gradation at your destination airport.

USER: Ok fine.

ASSISTANT: Thanks for reaching us, have a nice day.

USER: Thanks for your assistance.