You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be at your service today?

USER: Could you please change my existing reservation due to postpone of my exams?

ASSISTANT: May I know your name please to check the status of your reservation?

USER: My name is Rachel Harris.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Not a problem, thank you for checking.

ASSISTANT: Thank you for reaching us.