You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Joseph Martinez. Can you please help me in changing my existing reservation, as my football match got postponed to some other date.

ASSISTANT: Sure, I am here to help you. Hold on for a moment. Let me check.

USER: Sure, take your time.

ASSISTANT: Sorry Joseph Martinez, there are no flights reserved on your given name formerly.

USER: No problem, thanks for your information.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.