You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Larry Rodriguez, want to return from DEN to LAX. Please help me in booking my ticket.

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my trip dates are from 10/30 to 11/01.

ASSISTANT: Sorry, on these dates there is no flights available.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.