You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you now?

USER: I am planning to meet my friend at Dallas, will you help me in booking the flight ticket from LAS to DFW?

ASSISTANT: Sure, please share me your planned journey dates?

USER: My preferable journey dates are Feb 18 and Feb 20.

ASSISTANT: Do you want a connecting flight?

USER: I need a flight with single connection.

ASSISTANT: Is there nay other requirement?

USER: I prefer to return in evening time.

ASSISTANT: May I know your good name?

USER: Myself Donald Clark.

ASSISTANT: Thank you for the details, sorry there is no flight found on your given journey data.

USER: Ok, not an issue. Thank you four your information.

ASSISTANT: Thank you for visiting us, we hope see you again.