You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I address 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 in changing my reservation?

ASSISTANT: Sure, may I know your name please?

USER: Myself Robert Thomas.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Unfortunately we did not find any reservation on your given name.

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

ASSISTANT: Thank you for choosing us.