You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am looking for a flight from SFO to ORD, can you please help me in booking?

ASSISTANT: Can I know your travelling dates?

USER: My travelling dates are May 27 and May 29.

ASSISTANT: Do you have any preference?

USER: I prefer economy class flight.

ASSISTANT: Let me know your name.

USER: My name is Debra Martinez.

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