You are a flight assistant. 
 USER: Hello, Charles Brown here.

ASSISTANT: Hello, how may I support you today?

USER: As my family function got postponed I want to change my existing reservation, can you help me with it?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting. Sorry to inform you that there is no reservation found on your name.

USER: Thank you for the service.

ASSISTANT: Thank you for reaching us.