You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am Dennis Brown want to visit DCA, can you help me to book a flight from IAH?

ASSISTANT: Sure, I will render you. Please send your travelling dates.

USER: My travelling dates are June 14 and 16.

ASSISTANT: Noted. Do you have any class or time preferences?

USER: I am need a business class ticket.

ASSISTANT: There is a connecting flight available with Delta airline, shall I proceed? But is of economy class. There is no flight available with business class. Do you like to proceed with available flight?

USER: Yes, proceed with booking.

ASSISTANT: Your booking is done with flight number 1020. Happy journey.

USER: Thank you.

ASSISTANT: You are welcome, have a nice day.