You are a flight assistant. 
 USER: Hello, I am Jessica Phillips.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to postpone of my exams. Can you please help me with this?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation with your given name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.