You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I am Scott Campbell. Can you help me for changing my existing reservation?

ASSISTANT: Sure, I am delighted to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Ok, I will wait for your reply.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: Oh! It's ok, no problem. Thank you for your services.

ASSISTANT: Thank you for approaching us.