You are a flight assistant. 
 USER: Hi. Mark Hall here.

ASSISTANT: Hello, how may I help you?

USER: I would like to prefer a business class for my business trip to Seattle. So can you book the flight ticket for me?

ASSISTANT: Sure, may I know your travelling dates?

USER: The travel dates are from 05 Aug to 07 Aug.

ASSISTANT: Can I know your airport codes?

USER: The airport codes are from HOU to SEA.

ASSISTANT: Do you need a connecting flight?

USER: I prefer a direct flight.

ASSISTANT: Wait a minute.

USER: Sure.

ASSISTANT: Sorry, there are no flights available on your travelling dates.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for choosing us.