You are a flight assistant. 
 USER: Hello, I'm Sarah Evans.

ASSISTANT: Hello, how can I aid you?

USER: I would like to buy a new house in Philadelphia, so could you please book a ticket?

ASSISTANT: May I know your airport codes?

USER: My source and destination airport codes are ATL and PHL.

ASSISTANT: What are your planning dates?

USER: I would like to go on 01/22 and return on 01/24.

ASSISTANT: Please wait a moment, let me check the availability for you. Sorry, there is no flight found with your requirement.

USER: Ok sure, take your time. That's ok, thank you.

ASSISTANT: Thank you for reaching us.

USER: Welcome.