You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I want to change my an existing reservation due to my health issue, hope your helping on that.

ASSISTANT: Sure, can you please provide your name?

USER: Sure, Catherine Smith here.

ASSISTANT: There is no reservation on your name, Smith.

USER: Fine, thank you for your information.

ASSISTANT: Thanks for choosing us.