You are a flight assistant. 
 USER: Hello, Benjamin Smith here.

ASSISTANT: Hello, how can I help you?

USER: For a suddenly plan change, I want to change my reservation. Can you do this for me?

ASSISTANT: Yes sure. Wait a minute.

USER: Ok.

ASSISTANT: There is no reservation with your name.

USER: It's ok. Thank you.

ASSISTANT: Thank you to visit us.