You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you at this moment?

USER: I am planning to attend a live concert at Denver, can you help me to book a flight ticket within the fare limit 200?

ASSISTANT: Sure, I will help you but I need your travelling dates to search a flight.

USER: My trip dates are Dec 17th and Dec 19th.

ASSISTANT: May I know the airport codes of your current location and Denver?

USER: My airport codes are IAD-DEN.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: May I know your sweet name to proceed further?

USER: Jack Garcia here.

ASSISTANT: Based on your request, I could not find any flight for this route.

USER: No problem, Thanks for the information.

ASSISTANT: Thanks for choosing us, have a safe journey.