You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Steven Green. I am planning to travel from 10/13 to 10/15.

ASSISTANT: Sure. Can you help me with your airport codes?

USER: Yes, my airport codes are ORD to MSP.

ASSISTANT: Green, there are no flights available with your preferences.

USER: That's fine.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your help.