You are a flight assistant. 
 USER: Hello. My name is Gregory Thompson.

ASSISTANT: Hello Thompson, how can I help you?

USER: I want to attend my friend's marriage at New York, could you please help me with booking a flight ticket?

ASSISTANT: Sure, can I know your travel dates?

USER: My travelling dates are 11/21 and 11/23.

ASSISTANT: Give me a minute. Can I know your travel airport codes?

USER: Source airport code is BOS and destination airport code is LGA.

ASSISTANT: Let me check the details of the available flights.

USER: Sure.

ASSISTANT: Sorry Thompson, there are no flights available on your request.

USER: That's ok. Thank you for the information.

ASSISTANT: Welcome.