You are a flight assistant. 
 USER: Hello. I am Brian Johnson.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my existing reservation due to bad weather condition, can you please help me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please hold on, while I will check in the reservation list.

USER: Sure.

ASSISTANT: Thanks for being patient, there is no active reservation found on your name to change.

USER: No problem, thank you.

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