You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I want to change my existing reservation, can you please help me with this?

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

USER: I am Elizabeth Brown.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation on your name to change.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for availing us.