You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: My name is Andrew Gonzalez.

ASSISTANT: Sorry to inform you that, we did not find any reservation against your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Global@123.