how to retrieve confirmation ID

[vaida]

I booked an appointment for September for my US Visa interviews and I got all my documents. Later I found an earlier date and I changed it, but I failed to save/print the confirmation page (the one thats shows the date and time of the interviews, and I know I need to produce this at the embassy when I get there) Any ideas how to retrieve it? I can neither change nor cancel my appointment without it