You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Ashley Adams. Could you please help me in flight ticket booking process from LAS to DEN?

ASSISTANT: May I know on what dates would you like to travel?

USER: Thank you for your response, I want to take off on Sept 26 and book my return ticket also on Sept 28.

ASSISTANT: May I know your departure time and arrival time?

USER: I want to return in evening time.

ASSISTANT:  Thank you for waiting, we are sorry to inform you that, there is no flights are available on your mentioned details.

USER: Oh! It's ok no problem.

ASSISTANT: Thank you.

USER: Thank you for your information.