You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: This is Donna Garcia. I want to change an existing reservation due to postpone of my exams. Can you please help me in that?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.