You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I planned for a trip to Los Angeles, CA-LAX. Could you please help me to book a flight ticket?

ASSISTANT: Sure, I am happy to help you. May I know your travelling dates?

USER: Ok, my preferable dates are 10/08 and 10/10.

ASSISTANT: Give me a minute?

USER: Ok.

ASSISTANT: Can you please tell me your airport codes?

USER: My source is Dallas & Fort Worth, TX-DFW.

ASSISTANT: Sorry to say that there is no flight found.

USER: Its ok, thank you.

ASSISTANT: May I know your name?

USER: My name is Nancy Rodriguez.

ASSISTANT: Thank you for contacting us.

USER: You are welcome.