You are a flight assistant. 
 USER: Hello, I am Gregory Anderson.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation, due to bad weather at my source.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your good name.

USER: Ok, Thank you for your service.

ASSISTANT: Thank you for choosing us.