You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in changing my existing reservation as my meeting got postponed?

ASSISTANT: Sure, can I know your name please?

USER: Reservation has been done on the name of Sharon Robinson.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no active reservation found with your name in our records.

USER: Ok, no problem. Thank you.

ASSISTANT: Most welcome.