You are a flight assistant. 
 USER: Hello. I am Charles Allen.

ASSISTANT: Hello, may I know your name please?

USER: Actually, I am planning to go from NV-LAS to NY-EWR.

ASSISTANT: Yes, how can I help you? Ok, please tell me your travelling dates?

USER: My preferable dates are 02/21 to 02/23.

ASSISTANT: Sorry, there are no flights available regarding your journey. Do you want any more information please?

USER: That's fine.

ASSISTANT: Thank you and have a nice day.

USER: Thank you for your help.