You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: Please help me to change an existing reservation as my plan to meet my grand parents got postpone due to bad weather conditions.

ASSISTANT: Sure, I am here to help you with that, may I know your name to proceed further?

USER: I made a reservation by this name Daniel Brown.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.