You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Michelle hall, want to travel from BOS to LGA.

ASSISTANT: May I know your trip dates?

USER: My travelling dates are from 11/19 to 11/21.

ASSISTANT: Sorry, there is no flight available.

USER: That's fine, thank you.

ASSISTANT: Most welcome.