You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

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

ASSISTANT: Sure, can you share the travelling details?

USER: The travelling dates are from 08/25 to 08/27. My name is Benjamin Smith.

ASSISTANT: Sorry, there is no reservation found.

USER: Ok, no problem.

ASSISTANT: Thank you.

USER: I will check another flight.