You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I assist you today?

USER: I want to visit the science fair at Denver, please book me a flight ticket with a connection.

ASSISTANT: Sure, we are happy to help you. Can you please share your planned dates to travel?

USER: I want to travel on 08/02 and return on 08/04.

ASSISTANT: Do you have any restrictions in price limit?

USER: I need the ticket within price 200.

ASSISTANT: Kindly assign your airport codes?

USER: I want to fly from NV- LAS to CO- DEN.

ASSISTANT: Thanks for your details, please hold a moment, let me check with the airlines and let you know.

USER: Ok.

ASSISTANT: Thank you for waiting. We are sorry to inform you. we couldn't find any flights on your based guidelines.

USER: No issues, thank you for the information.

ASSISTANT: Thank you for reaching us. Have a nice day.