You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am Donna Robinson, want to travel from HOU to LAS. Can you please help me?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My trip dates are from Aug, 27 to Aug, 29.

ASSISTANT: Do you have any preferences?

USER: I have only 1 preference which is a single halt in between my journey.

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

USER: That's fine, thank you.

ASSISTANT: You are welcome, have a nice day.