You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Nancy Miller. I am planning to book a ticket with price of 200. Can you please help me out to book a ticket?

ASSISTANT: Miller, can you please let me know your source and destination airport codes?

USER: My nearest source cod is SEA and my destination code is MCO.

ASSISTANT: Ok, let me know your travel dates.

USER: I would like to travel on 09/21 and return back on 09/23.

ASSISTANT: Miller, there are no flights available on your preferred dates.

USER: That's fine. Thank you for your help.

ASSISTANT: Thank you very much for contacting us and have a nice day.