You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your good name?

USER: My name is Patricia Brown.

ASSISTANT: How can I be of your assistance?

USER: I need to change my existing reservation can you help me for change my reservation?

ASSISTANT: Ok, Wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting. Unfortunately, There is no reservation found with your name.

USER: Thanks for your information.

ASSISTANT: Thanks for reaching us.