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

ASSISTANT: Hello, how may I help you today?

USER: I want to change my reservation, due to postpone of my trip with friends. Can you please help me with that?

ASSISTANT: Sure, I will help you with that. Please wait for a minute.

USER: Thank you. Sure.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: Sorry to say this, there is no reservation found on your name.

USER: Ok, no issue. Thank you for your information.

ASSISTANT: Thank you for choosing us, have a good day.