You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help 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: Can I know your name?

USER: Helen Garcia here.

ASSISTANT: Sorry, there is no reservation by your name.

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

ASSISTANT: Thank you.