You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kenneth White.

ASSISTANT: How may I help you today?

USER: Can you please help me in booking a flight ticket to LAS from DEN?

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

USER: My travel dates are from Jan 11 to Jan 13.

ASSISTANT: Do you need any connection limit?

USER: I need a single connecting flight.

ASSISTANT: May I know your depart and arrival time?

USER: I would like to return in the evening.

ASSISTANT: May I know your class preference?

USER: I am comfortable with any class.

ASSISTANT: Do you have any specific airline?

USER: No.

ASSISTANT: Sorry to inform you that there are no flight services available on your given details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for opting us.