You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Mark Young from Houston. Can you please check the availability of flights in between the points from HOU to LAS?

ASSISTANT: May I know your desired travel dates please?

USER: Sure, I have a plan to travel on 22 and 24 on the month of May.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: That's Ok, I will choose another alternative to go.

ASSISTANT: Thank you for opting us.

USER: Thank you.