You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am planning to visit Houston NASA Space Center with my students at HOU. can you help me with booking?

ASSISTANT: Sure, may I know your trip dates please?

USER: My trip dates are Mar 02 and Mar 04.

ASSISTANT: Please let me know your Source airport code.

USER: My source airport code is LAX.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Ok, no issues.

ASSISTANT: Can I know your name please?

USER: Thank you. I am Margaret Lewis.

ASSISTANT: Ok, thank you.