You are a flight assistant. 
 USER: Hello. I am Charles Perez.

ASSISTANT: Hello, how can I assist you at this moment?

USER: I want to visit Denver city to meet my best friend. Can you make a reservation for me?

ASSISTANT: Sure, may I know your preferable airport codes, please?

USER: Sure, I want to start my journey from New York JFK to reach Denver DEN.

ASSISTANT: Can you please mention your travelling dates?

USER: Ok, my planned trip dates are on June 02 and return on June 04.

ASSISTANT: Do you have any specification?

USER: Yes, I can afford only 200 for the flight ticket.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your own time.

ASSISTANT: There is a connecting flight available in Frontier airline with a fare of 200. Can I book it?

USER: I want a economy class, can you check with that?

ASSISTANT: Sure, I will check and revert back to you.

USER: Ok.

ASSISTANT: Your ticket is booked with economy class and the flight number is 1015.

USER: Ok, thank you for your valuable help.

ASSISTANT: Thank you for reaching us, have a safe journey.