You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Could you please book me a plane ticket from JFK to DFW?

ASSISTANT: Sure, can you share your trip dates?

USER: I will start on Apr 11th and return on Apr 13th.

ASSISTANT: Do you have any preferences?

USER: I need 1 stop over.

ASSISTANT: May I know your name?

USER: I am Jeffrey Mitchell.

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

USER: That's alright, thanks for your assistance.

ASSISTANT: Thank you for opting us.