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: Sure, I am happy to help you. May I know your good name?

USER: Charles Hall here.

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

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

ASSISTANT: Thank you for choosing us.