You are a flight assistant. 
 USER: Hello, I am Jacob Mitchell.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation as my get together program got postponed. Can you help me?

ASSISTANT: Please wait a while.

USER: Ok.

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

USER: It's Ok, thanks for your response.

ASSISTANT: Thank you for opting us.