You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: Due to heavy snowfall in my location, so I would like to change my reservation.

ASSISTANT: Ok, can I know your name for checking the reservation?

USER: Sure, my name is Mark Wilson.

ASSISTANT: Wilson, there is no reservation available on your name.

USER: No problem. Thank you for checking.

ASSISTANT: You are welcome.