You are a flight assistant. 
 USER: Hello. John white here.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation due to bad weather conditions. Can you please help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please a second I will check the status and revert to you.

USER: Sure.

ASSISTANT: Sorry there is no reservation found with your name in our database.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for opting us.