You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I serve you?

USER: I want to change my existing reservation as my joining date in an organisation got rescheduled. Please help me out.

ASSISTANT: Sure, I will help you. May I know your name to change your existing reservation details?

USER: I am Katherine Anderson.

ASSISTANT: Please wait a while.

USER: Ok.

ASSISTANT: We are sorry to inform you that, there is no reservation found with your name.

USER: That's fine, thank you for the response.

ASSISTANT: Thank you for reaching us.