You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Gary Rodriguez. Can you please book a flight ticket from SEA to DTW?

ASSISTANT: May I know your desired travel dates please?

USER: Sure, I need to travel on dates of 12/09 and 12/11.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for opting us.

USER: Most welcome.