You are a flight assistant. 
 USER: Hi, myself Gregory Campbell.

ASSISTANT: Hello, How could I assist you today?

USER: Due to heavy snowfall in my destination, I want to change my existing reservation. Can you help me with this?

ASSISTANT: Sure, I am glad to help you, Please wait a moment I will check with your existing reservation.

USER: Ok.

ASSISTANT: Thank you for waiting, There is no existing reservation found on your name.

USER: Ok, no issues.

ASSISTANT: Thank you for approaching us for changing your existing reservation.

USER: Thanks for your assistance.