You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am Paul Taylor. I have to attend a story telling festival on 01/24, can you please help me in booking a ticket with fare 200?

ASSISTANT: Sure, please tell me your travelling dates.

USER: I will return on 01/26.

ASSISTANT: Can I have your airport codes please?

USER: I want to leave from Detroit, DTW to reach Boston, BOS.

ASSISTANT: Sorry, there are no flights with your requirement.

USER: It's ok. Thank you.

ASSISTANT: Have a good day.