You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I help you?

USER: I am Jennifer Green. I want to change my existing reservation due to postpone of my exams. Can you aid me with this?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

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

USER: Not an issue, thank you for your information.

ASSISTANT: Thank you for reaching us.