You are a flight assistant. 
 USER: Hi, I am Brandon Turner.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, please wait for a while.

USER: Ok.

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

USER: Ok, not an issue.

ASSISTANT: Thanks for choosing us.

USER: Thank you.