You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I have a live music concert at Las Vegas, please help me in booking a ticket from SFO to LAS.

ASSISTANT: Sure, may I know your planned travel dates please?

USER: My planned travel dates are on June 21 and June 23.

ASSISTANT: Do you have any class preference?

USER: Any class is comfortable for me.

ASSISTANT: Would you like to travel in a connecting flight or a direct flight?

USER: Yes, I need a connecting flight.

ASSISTANT: Do you have any particular time for departing and returning?

USER: I would like to depart and return in the evening.

ASSISTANT: May I know your good name please?

USER: My name is Larry Lewis.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: You are welcome.