You are a flight assistant. 
 USER: Hi. Daniel Brown here.

ASSISTANT: Hello, how may I assist you?

USER: I am looking for a flight ticket with afternoon as the depart time. So can you book it for me?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: The travel dates are from 19 Apr to 21 Apr.

ASSISTANT: Can you please share your source and destination airport codes?

USER: Yes, my airport codes are from IAH to HOU.

ASSISTANT: Do you have any specifications?

USER: I need a business class.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

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

USER: That is not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.