You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your name?

USER: I'm Matthew Green.

ASSISTANT: OK, Green tell me how may I help you?

USER: I am planning to visit my cousin's marriage and searching to book a flight ticket from MI- DTW to MA- BOS.

ASSISTANT: OK, can you please tell me your travelling dates?

USER: Sure. My departure month/day should be 09/17 and my return month/day must be 09/19.

ASSISTANT: Sorry to say, there is no flight found on your travelling dates.

USER: It's OK. Thank you for your information.

ASSISTANT: Thank you for contacting us.