You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: Frank Miller here, please help me out in booking the ticket from LAS to CLT.

ASSISTANT: Sure, can you please share your travel dates?

USER: My trip dates will be Dec 18 to Dec 20.

ASSISTANT: May I know your class preference?

USER: Economy is my class preference.

ASSISTANT: May I know your connection limit?

USER: Flight has to be with single connection.

ASSISTANT: Do you have any other specification that you are looking for?

USER: My depart and return time must be in the Afternoon and morning.

ASSISTANT: Frank Miller, I am sorry to inform you that there is no flight available at your request.

USER: That's ok, thank you.

ASSISTANT: You are welcome. Thank you for contacting us.