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

ASSISTANT: Hello, how can I assist you today?

USER: My exams has been postponed. I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your name.

USER: Not a problem, thank you.

ASSISTANT: Thanks for choosing us.