You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I am looking for a flight which is travelling from Washington to Detroit. Can you please help me?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: Thank you. I am planning to travel on the dates of June 10 and June 12.

ASSISTANT: Can I know your airport codes please?

USER: The source and destination airport codes are DCA and DTW.

ASSISTANT: Do you need any specifications in airlines?

USER: No but I need a flight which is having a single connection limit.

ASSISTANT: Can I know  your name please?

USER: My name is Mary Scott.

ASSISTANT: Sorry, there are no flights found in our database.

USER: It's ok, not a problem with that. Thank you for spending your valuable time.

ASSISTANT: Thank you for reaching us.