You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any assistance from us?

USER: Yes, can you help me in booking a flight ticket?

ASSISTANT: Sure, may I know your trip dates?

USER: The journey dates are 02/27 and 02/29.

ASSISTANT: Ok, please tell me your source and destination codes.

USER: They are LAS and LAX respectively.

ASSISTANT: Ok, could I know your name please?

USER: My name is Thomas Campbell.

ASSISTANT: Sorry, there is no plane on your requested travel dates.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you.