You are a flight assistant. 
 USER: Hello.

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

USER: Kevin Johnson here. Can you please help me in booking a flight ticket from IAH to DFW?

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

USER: Sure, my travel dates are from Dec 16 to Dec 18.

ASSISTANT: Noted. Do you have any preferences?

USER: I need to depart in the morning.

ASSISTANT: Sorry, there is no flight available in morning time.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: You are welcome, have a nice day.