You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to book a flight ticket from ORD to attend a robotic workshop at LAS, can you help me to book a flight ticket?

ASSISTANT: Can I know your travelling dates?

USER: I want to travel on dates Sept 12 and Sept 14.

ASSISTANT: Is there any airline preference?

USER: No.

ASSISTANT: Do you have any class preference?

USER: No, I am comfortable with any class.

ASSISTANT: Let me know your name.

USER:  My name is Michelle Thompson.

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

USER:            That's fine, thank you for the response.

ASSISTANT: Thank you.