You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation because my trip got postponed. Can you aid me?

ASSISTANT: Sure I help you out, please provide me your name to check the reservation details on your name.

USER: Myself John Jackson.

ASSISTANT: Sorry John, no reservation found on your name.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for reaching us.