You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, good morning. How can I assist you for today?

USER: I have planned a trip with my ex-colleagues who are staying at Chicago, can you help me in booking a ticket from DEN to ORD?

ASSISTANT: Sure, I will help you with that. May I know your name for booking the flight ticket?

USER: Myself Donna Thompson.

ASSISTANT: Ok, may I know the preferable dates of your journey?

USER: I want to travel on 09/18 and return on 09/20.

ASSISTANT: Sorry Donna, there are no flights found on your requirement.

USER: No problem, I will try another way to complete my trip. Thank you for checking.

ASSISTANT: I like your positive attitude, thank you for approaching us. You are welcome.