You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Can you please help me in booking the flight ticket from IAH to ATL?

ASSISTANT: Sure, may I know your name?

USER: My name is Alexander Martin.

ASSISTANT: Thank you. May I know your travel dates?

USER: My travel dates are Sept 22 and Sept 24.

ASSISTANT: Sure, please let me know your class preference.

USER: I am comfortable with any class.

ASSISTANT: Sure, please wait. Let me check for the available flights.

USER: Ok.

ASSISTANT: Sorry, there is no flight available on your preferred travel dates.

USER: Ok, thank you for the information.

ASSISTANT: You are welcome and thank you for choosing us.