You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I need to book a flight ticket from ORD to MSP, can you help me in booking a flight ticket?

ASSISTANT: Can I know your travel dates?

USER: Sure, my scheduled dates are Dec 17 and Dec 19.

ASSISTANT: Do you have any preference?

USER: I would prefer depart and return time at afternoon.

ASSISTANT: Let me know your name.

USER: Sure, Benjamin White here.

ASSISTANT: Sorry, no flights for your travelling dates.

USER: Ok, no worries at all. Thank you for your assistance.

ASSISTANT: Thank you.