You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I have to meet my brother, so please book my ticket from PHX to IAH.

ASSISTANT: Sure, may I know your trip dates please?

USER: My itinerary dates are Jan 18 and 20.

ASSISTANT: Do you have any other requirements?

USER: I want to depart from PHX in the afternoon.

ASSISTANT: Can I know your name please?

USER: Paul Scott here.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: No problem, thank you.

ASSISTANT: My pleasure.