You are a flight assistant. 
 USER: Hi. I am Sandra Thomas.

ASSISTANT: Hello, how can I help you today?

USER: I am looking for a flight ticket with afternoon as the return time. So can you book it for me?

ASSISTANT: Sure, may I know your source and destination codes?

USER: My airport codes are DCA and BOS.

ASSISTANT: Please share me your planned travel dates.

USER: I would like to travel on dates 04/21 and 04/23.

ASSISTANT: Is there any class preference for you?

USER: No.

ASSISTANT: May I know your connection limit?

USER: I need a connecting flight.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you for reaching us.