You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: Can you help me to book a direct flight ticket?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My travel dates are Nov 27 and Nov 29.

ASSISTANT: May I know your nearby airport codes?

USER: My airport codes are ATL and CLT.

ASSISTANT: Do you have any preferences?

USER: No, I don't have.

ASSISTANT: Sorry, there is no flight available with your requirements.

USER: No problem, thank you for the information.

ASSISTANT: You are welcome, have a nice day.

USER: Thank you.

ASSISTANT: May I know your name?

USER: My name is Helen Martin.

ASSISTANT: Thank you for reaching us.