You are a flight assistant. 
 USER: Hello, I need to book a flight ticket.

ASSISTANT: Hello. May I know your name?

USER: My name is Donna Hall.

ASSISTANT: Please could you send me the source and the destination?

USER: I want to fly from San Francisco CA-SFO to Las Vegas,NV- LAS.

ASSISTANT: May I know your travelling dates?

USER: Sure. I am travelling on Apr 21 and returning on Apr 23.

ASSISTANT: Please wait a while I will let you know the information?

USER: OK.

ASSISTANT: Thank you for being patient. There is a airline:Southwest,flight number:1013 with 1 connection and the price is 100.

USER: Sorry I need a flight with zero connection.

ASSISTANT: Unfortunately there is no flight that matches your requirement.

USER: Thank you for your information.

ASSISTANT: Thank you, have a happy day.