You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: Due to sudden change of my business meeting because of some technical problem, I need to change my reservation so can you help me with that?

ASSISTANT: May, I know your good name?

USER: I am Jeffrey Johnson.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.