You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I want to book a direct flight ticket to attend an emergency case at MA. Can you help me?

ASSISTANT: Let me know your travelling dates.

USER: Sure, July 30th and Aug 01st are my trip dates.

ASSISTANT: Do you have any preference?

USER: No.

ASSISTANT: Can I know your travelling codes?

USER: MSP and BOS are my airport codes.

ASSISTANT: Let me know your name.

USER: George Green.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: No issue.

ASSISTANT: Thank you.

USER: Thank you.