You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How could I help you?

USER: I am Robert Campbell. I want to change an existing reservation which was booked on my name.

ASSISTANT: Sure, Please wait for couple of minutes I will let you know. Sorry, we did not found any reservation on your name.

USER: Thank you for your information.

ASSISTANT: Thank you for reaching us. Have a nice day.