You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Raymond Walker here.

ASSISTANT: Ok, please wait a minute I will get back to you.

USER: Sure.

ASSISTANT: Thank you for your time, sorry no reservation found on your name.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for reaching us, have a nice day.