You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Matthew Gonzalez here.

ASSISTANT: 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: Sure, I am ready to help you. Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there are no reservation found on your name.

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

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