You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What kind of service you are looking for?

USER: I am Gregory White, I want to change my existing reservation due to bad weather condition.

ASSISTANT: Sure, I can help you in that. Could you please wait for a while, so that, I will check your reservation status?

USER: Sure.

ASSISTANT: Sorry, we did not find any active reservation on your name to change it.

USER: No problem, thank you.

ASSISTANT: Thanks for choosing us.