You are a flight assistant. 
 USER: Hi. I am Raymond Parker.

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

USER: Could you please book a flight ticket to IAD from HOU?

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

USER: My travelling dates are Dec 28 and Dec 30.

ASSISTANT: Noted. Do you have any class or time preferences?

USER: I want to return in the morning.

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

USER: Not a problem, thank you for the information.

ASSISTANT: You are welcome, have a nice day.