You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, may I know how best I can help you today?

USER: As I am a doctor I need to fly with the direct flight to Minneapolis to treat an emergency case, can you help me with the booking?

ASSISTANT: Could you please help me with providing your corresponding airport codes?

USER: My plan to start from Denver, CO-DEN to reach Minneapolis, MN-MSP.

ASSISTANT: How much you can spend for airfare?

USER: I can spend up to 500.

ASSISTANT: When are you planning to make your journey? Thank you for providing your details, please wait for a while.

USER: 03/27 and 03/29 are my planned travelling dates. Ok.

ASSISTANT: Thank you for your time. Let me know your good name please.

USER: I am Paul lee.

ASSISTANT: Thank you. We did not find any flights matching your credentials.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us.