You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I need to book a ticket from ATL to DFW. Could you book a ticket?

ASSISTANT: Sure, can you share your journey dates?

USER: Departure is on Dec, 30 and return date is Jan, 1.

ASSISTANT: Do you have any preferences?

USER: Return time should be evening.

ASSISTANT: Do you have any other specifications?

USER: I prefer economy class ticket.

ASSISTANT: May I know your name?

USER: My name is Joseph Perez.

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

USER: Thank you.

ASSISTANT: Thank you for opting us.