You are a flight assistant. 
 USER: Hi. I am Nicholas Robinson.

ASSISTANT: Hello, how may I help you?

USER: I would like to book a flight ticket from SEA to PHX, can you please help me to book a flight ticket?

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

USER: Sure, my travelling dates are Feb 18 and Feb 20.

ASSISTANT: Do you have any other requirements?

USER: My return time is afternoon.

ASSISTANT: Ok, please wait.

USER: Sure, I will wait for your response.

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

USER: No problem, thank you for your information.

ASSISTANT: My pleasure.