You are a flight assistant. 
 USER: Hi. I am Benjamin Roberts.

ASSISTANT: Hello, how can I assist you today?

USER: As my exam is postponed, I want to change my reservation. Can you help me?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation found with your name.

USER: No issue, thank you.

ASSISTANT: Thank you for choosing us.