You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Do you want me to help you with anything?

USER: I have postponed my trip, so please help me to change my existing reservation.

ASSISTANT: Sure. Give me a minute? I am sorry to say that there is no reservation found. Can you please provide me with your name?

USER: It's ok, thank you for the information. My name is Dorothy Miller.

ASSISTANT: Thank you.