You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I help you?

USER: My name is Joshua Clark. My business trip was cancelled, so please help me for change an existing reservation.

ASSISTANT: Sure, please wait a moment.

USER: OK sure.

ASSISTANT: We found a existing reservation on your name. May I know your new journey details?

USER: Sure, my source and destinations are NC-CLT, TX-AUS. And my departure day is 11/22, return day is 11/24.

ASSISTANT: Flight number:1004 with Frontier airlines. Price limit 300 with single connection. Shall I confirm your ticket?

USER: Yes please.

ASSISTANT: OK. your ticket has been confirmed.

USER: Thank you for your service.

ASSISTANT: Have a nice journey.