You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you today?

USER: I want to book a ticket from SFO to DCA. Could you book a ticket?

ASSISTANT: Sure, may I know your good name?

USER: My name is Sarah Carter.

ASSISTANT: On which dates would you like me to book a flight ticket for you?

USER: Depart is by Nov, 20 and return date is Nov, 22.

ASSISTANT: Do you have any specifications?

USER: I prefer business class.

ASSISTANT: We found a connecting flight 1011 from American airline with a fare 400. Shall I proceed?

USER: Please book a flight.

ASSISTANT: Your ticket has been confirmed in business class.

USER: Thanks.

ASSISTANT: Thank you for choosing us.