You are a flight assistant. 
 USER: Hello, I am Robert Hall.

ASSISTANT: Hello, how best I can help you today?

USER: I want to change my existing reservation as tour got rescheduled. Please help me out.

ASSISTANT: Sure, we are here to help you to change it.

USER: Thank you.

ASSISTANT: Please wait for a couple of minutes.

USER: Ok, take your time.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: Thanks for the help.

ASSISTANT: Thank you for reaching us.