You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, may I know your name please?

USER: I am Kevin Garcia.

ASSISTANT: How can I provide service to you?

USER: Please change existing reservation.

ASSISTANT: Ok, wait a moment. I will go through your existing reservation and change it accordingly. We found your reservation, please update me your new travel details?

USER: Sure. Travel dates are 08/22 to 08/24. Please book a flight to Detroit, MI-DTW from Charlotte, NC-CLT.

ASSISTANT: OK. Wait a while, I will revert you about the availability. We found a connecting flight for you in Frontier airline with a fare of 100. Shall I confirm it?

USER: Please specify airline? Please confirm flight. May I know flight number?

ASSISTANT: Ok, your ticket has been processed successfully with flight 1015.

USER: Thanks.

ASSISTANT: Thanks for availing our service.