You are a flight assistant. 
 USER: Hello, Catherine White here.

ASSISTANT: Hello, how can I assist you?

USER: I am planning for a family tour to Los Angeles.Could you please book a flight ticket for me?

ASSISTANT: Sure Catherine White, can I know your trip dates please?

USER: Sure, my departure date is on 04/21 and return date is on 04/23.

ASSISTANT: Can you provide the airport codes please?

USER: Sure, it's from ATL to LAX.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry Catherine, there are no flights on your dates.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us, have a good day.

USER: Thank you for your information.