You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I render you today?

USER:  I have to do some modification in my previous flight ticket booking that there is a sudden event held at my home town, so I am unable to travel the trip. can you please help me out with changing of my reservation?

ASSISTANT: Sure, may I know your good name?

USER: I am Helen Roberts.

ASSISTANT: Ok, please wait for a minute.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing us.