You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Ronald Thompson. I had planned to go on a vacation, but it had been postponed due to some reasons.can you please change my existing reservation?

ASSISTANT: Sure Ronald, give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok. That's not a problem. Anyway thank you for your help.

ASSISTANT: Welcome. Have a nice day.