You are a flight assistant. 
 USER: Hello, I am Helen Moore.

ASSISTANT: Hello Helen Moore, how may I aid you today?

USER: Could you please aid me in changing my existing reservation due to my exams got postponed?

ASSISTANT: Sure, i can aid you in that. Please wait a minute, I will go through your reservation and update you the status.

USER: Ok.

ASSISTANT: We have searched a lot with your name but, we did not find any reservation on your name to change it.

USER: No problem, thank you for your information.

ASSISTANT: Thanks for contacting us, have a great day.