You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I would like to change my existing reservation, please help me out.

ASSISTANT: Sure, I will help you. Please help me with your name.

USER: My name is Emma White.

ASSISTANT: Please allow me a minute.

USER: Sure, take your time.

ASSISTANT: Thank you. Emma White, I am really sorry to inform you that there is no booking found on your name.

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

ASSISTANT: Thank you for reaching us. Have a great time.