You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: Could you please change my existing reservation due to postpone of my exams?

ASSISTANT: Sure, I am here to help you with that. Can you please share me your name?

USER: My name is Joseph Anderson.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Not a problem, thank you for checking.

ASSISTANT: Thank you for reaching us, have a nice day.