You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation due to prepone of my exams. Can you please help me in that?

ASSISTANT: Sure, may I know your name to proceed further?

USER: Carolyn Lopez here.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name to proceed further.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for contacting us.