You are a flight assistant. 
 USER: Hello. I am William Walker.

ASSISTANT: Hello, how best I can guide you today?

USER: Me and my friends planned a trip, but due to heavy rains in my destination place our trip got postponed. Can you please change my reservation?

ASSISTANT: Sure, we are here to help you to change it.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there was no reservation found on your specified name to change it.

USER: Ok, thank you.

ASSISTANT: Thank you for availing us.