You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Please help me to book a flight from DTW to IAD.

ASSISTANT: Sure, may I know your planned trip dates?

USER: Sure, I want to travel on July 1 and need to return on July 3.

ASSISTANT: Let me know your connection limit?

USER: I need a flight with single connection.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: May I know your good name?

USER: My name is Christopher Hernandez.

ASSISTANT: Any other requirements to be met?

USER: My return time must be in the evening.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for reaching us.