You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you today?

USER: I am  Paul Thompson. I want to change my existing reservation as my joining date in an organisation got rescheduled.

ASSISTANT: Ok, please wait a moment.

USER: Ok, take your time.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: That's fine, thank you for your service.

ASSISTANT: Thanks for reaching us, have a good day.