You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Mary Smith here.

ASSISTANT: How can I help you?

USER: Could you book my ticket in business class?

ASSISTANT: Let me know your airport codes.

USER: I want to travel from PHL to ATL.

ASSISTANT: Can I know your travelling dates?

USER: My trip dates are Nov 24 and Nov 26.

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

USER: No problem, thank you.

ASSISTANT: Thanks.