You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I would like to book a flight ticket from SFO to DCA, can you help me with that?

ASSISTANT: Sure, let me know your planned journey dates?

USER: My trip dates are 10/29 and 10/31.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: Is there any time concern?

USER: I prefer economy class, and my return time must be in evening.

ASSISTANT: Can I know your name?

USER: I am Anna Johnson.

ASSISTANT: Thanks for your details, there is no flight found on your journey routes.

USER: That's ok. Thank you for your service.

ASSISTANT: Thank you for reaching us.