You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how best I can help you today?

USER: Could you help me to amend my existing reservation?

ASSISTANT: Sure, I can change your reservation right now. Before that I need to know your good name please?

USER: My name is David Garcia.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Not a problem, thank you.

ASSISTANT: Thank you for availing us.