You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello, how can I help 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: Let me know your name to check your reservation?

USER: Angela Hernandez here.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

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: That's ok, thank you for your help.

ASSISTANT: Thank you for choosing us.