You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you today?

USER: I am Kevin Green. Can you please help me in changing my existing reservation? As my plans to visit Los Angeles got postponed.

ASSISTANT: Sure, I'll help you with this. Please wait a moment.

USER: Sure, I will wait for your information.

ASSISTANT: I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Oh! That seems something went wrong while booking the ticket previously. Thank you for providing information.

ASSISTANT: Thank you for opting us.