You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Christine White. I want to change my existing reservation, can you help me with that?

ASSISTANT: Sure, I will help you to change your reservation. Please allow me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: No issue, thank you for the information.

ASSISTANT: Welcome, have a nice day.