You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you today?

USER: Can you please help me in booking my flight ticket from OAK to DCA?

ASSISTANT: Sure, may I know your good name?

USER: Sure, myself Alexander Martin.

ASSISTANT: Please let me know your connection limit?

USER: I need a single connecting flight.

ASSISTANT: Could you please provide your preferred dates of travel?

USER: My travelling dates are from 09/17 to 09/19.,.

ASSISTANT: Do you have any more specifications?

USER: I would like to prefer business class.

ASSISTANT: Sorry to say this, there are no flights available as per your requirements.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for opting us.