You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Can you please help me with booking a flight ticket from IAD to MSP?

ASSISTANT: Sure, can you share your trip dates?

USER: My planned trip dates are Dec 10 and Dec 12.

ASSISTANT: Do you have any preferences?

USER: I need a direct flight in my journey.

ASSISTANT: May I know your name?

USER: My name is Melissa Thompson.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us.