You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Can you help me to change my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: I am George Garcia.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there is no active reservation found under your name.

USER: That's ok, thank you.

ASSISTANT: Most welcome.