You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Patrick Phillips here. 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, I will help you to change your reservation.

USER: Ok.

ASSISTANT: Please give me a moment. Sorry, no reservation found on your name to change your reservation.

USER: No issues. Thank you for checking.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.