You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Brian Young here. I want to change my existing reservation due to some bad weather conditions. Can you help me in that?

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for your time, there is no active reservation found in your name to change.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for reaching us, we hope to serve you again.