You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Can you help me to book a flight ticket from DCA to OAK?

ASSISTANT: Sure, we are here to help you. Can you please let me know your travelling dates?

USER: My travel dates are May 29 and May 31.

ASSISTANT: Do you have any connection limit?

USER: I prefer connecting flight between my journey.

ASSISTANT: May I know your good name?

USER: My name is Barbara Brown.

ASSISTANT: Please help me with your class preference.

USER: I am comfortable with any class.

ASSISTANT: Is there any other specifications for you?

USER: No.

ASSISTANT: Thanks for providing details, no flights are available on your journey routes.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.