You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you today?

USER: Owing an emergence, I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, I will help you in changing your previous reservation. May I know your name?

USER: My name is Anthony Edwards.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found in our  reservation database.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for approaching us, have a nice day.