You are a flight assistant. 
 USER: Hi.

ASSISTANT:  Hello, how can I assist you today?

USER: I am Barbara Turner.

ASSISTANT: Ok.

USER: I would like to change my existing reservation, due to my sport event has been postponed. Could you please help me in changing?

ASSISTANT: Sure, I would help you with that. Please wait a while.

USER: Sure.

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

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for reaching us, Have a blissful day!.