You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you?

USER: My holiday vacation has been postponed.Can you please help me for changing the existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: My name is Dennis Jackson.

ASSISTANT: Sorry Dennis, no reservation has been found on your name.

USER: Ok, no problem. I will search another flight. Thank you for your information.

ASSISTANT: Ok, thank you for approaching us.