You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my reservation, can you help me?

ASSISTANT: Sure, may I know your name please?

USER: Myself Joseph Lee.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry Lee, there is no reservation found as per your name to change your reservation.

USER: No problem, thanks for checking.

ASSISTANT: You are welcome.