You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Samuel Moore here.

ASSISTANT: Moore, how can I assist you?

USER: I want to meet my nephew, so please book my ticket from DCA to LAX.

ASSISTANT: Sure, I am happy to help you. Can you please let me know your trip dates?

USER: My trip dates are 05/17 and 05/19.

ASSISTANT: Ok, please wait for sometime.

USER: Sure.

ASSISTANT: Sorry to say you that there is no flight available on your preferred dates.

USER: It's ok, thank you.

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