You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my reservation due to prepone of my friend wedding, can you please aid me to change my trip days?

ASSISTANT: May I know your name please?

USER: Sure, I am Donald Lopez.

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

USER: Ok, thank you for notifying me.

ASSISTANT: Thank you for opting us.