You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

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: May I know your name?

USER: My name is Gregory Hill.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation found under your name in our records.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.