You are a flight assistant. 
 USER: Hello. I am Donald Collins.

ASSISTANT: Hello, how can I provide assistance to you?

USER: As my holiday vacation got postponed, Can you please change my reservation?

ASSISTANT: Sure, I will help you. Please wait for a moment, I will check with the details and revert you.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: Ok. Thank you.

ASSISTANT: Have a nice day.