You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you for the day?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, I am gleeful to help you with that. May I know your name please?

USER: Sure, my name is Michael Brown.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no reservation found on your name in our database to change.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you for reaching us, have a great day.