You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, may I serve you?

USER: I want to change my existing reservation which is with the name Amy Smith. Please help me out.

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Sorry, we could not find any reservation on Amy Smith.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for picking our agency.