You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I need to book a flight ticket from IAD to ATL, Can you please help me for booking?

ASSISTANT: Sure, can you share your journey dates?

USER: I would like to travel on 01/03 to return on 01/05.

ASSISTANT: Do you have any preferences?

USER: I need a economy class with return on afternoon.

ASSISTANT: May I know your name?

USER: Rebecca Martin.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for opting us.