You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Larry Adams.

ASSISTANT: Adams, how may I assist you today?

USER: I am planning for a visit to Fort Worth to meet my friend.Can you please help me to book the flight ticket on 04/17 and 04/19?

ASSISTANT: Sure, may I know your airport codes?

USER: My airport codes are LAX and DFW.

ASSISTANT: Sorry Adams, no flights as per your requirements.

USER: That's ok. Thank you for your information.

ASSISTANT: You are welcome.