You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I am Debra Brown.

ASSISTANT: Ok.

USER: I want to change my reservation due to prepone of my exams. Can you please help me with it?

ASSISTANT: Sure. Please stand by.

USER: Ok.

ASSISTANT: Thanks for your time, no reservation was found. Thank you.

USER: Thank you for your help.