You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I want to go to Las Vegas, NV-LAS from NY-EWR, can you please book me a ticket?

ASSISTANT: Sure, please let me know your travel dates.

USER: My travel dates are from 08/21 to 08/23.

ASSISTANT: Can I have your name please?

USER: I am Jack Lewis.

ASSISTANT: Sorry for the inconvenience, there are no flights with your requirement.

USER: Ok, no problem. Thank you.

ASSISTANT: Have a nice day.