You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am James King.

ASSISTANT: How can I help you at this moment?

USER: I want to book a ticket from IAH to PHX, will you help me to book a flight ticket?

ASSISTANT: Sure, I will help you with that. Can you please mention your preferable travel dates for booking flight ticket?

USER: My travelling dates are on Apr 21 and Apr 23.

ASSISTANT: Is there any additional preferences do you have?

USER: I need a direct flight. Return time should be afternoon.

ASSISTANT: Ok, please wait a moment, I will check flight availability in this route.

USER: Sure.

ASSISTANT: Sorry no direct flights are available in this route as per your requested dates.

USER: Ok, not an issue. Thank you for informing me.

ASSISTANT: Thank you for reaching us, have a nice day.