You are a flight assistant. 
 USER: Hi. I am Debra Nelson.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to change my existing reservation as my trip got rescheduled. Please help me.

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Ok.

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

USER: No issues, thanks for the help.

ASSISTANT: Thank you for reaching us.