You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Ronald Hill.

ASSISTANT: How may I guide you today?

USER: Can you help me in changing my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please wait for a minute/. I am sorry to say that there is no reservation found.

USER: Ok. That's ok, thank you.

ASSISTANT: Thank you for contacting us.