You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I am Nicole Thomas want to visit Millennium Park at Chicago, can you book a ticket with price under 200?

ASSISTANT: Ok, please provide your travelling dates to go.

USER: Sure, my travelling dates will be 08/15 and 08/17.

ASSISTANT: Can I have your airport codes?

USER: Yes, I want to fly from PHX to ORD.

ASSISTANT: Thanks for your data, there is no flight for you according to your requirements.

USER: That's ok, thank you.

ASSISTANT: Welcome, have a good day.