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

ASSISTANT: Hello, how may I help you at this moment?

USER: Due to an emergency meeting, I want to change my reservation. Can you help me with it?

ASSISTANT: Sure, i am here to help you. Please wait a while.

USER: OK.

ASSISTANT: Sorry, no reservation has been registered with us on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thanks for approaching us, have a nice day.