<p>Okay so I was registered for the SAT on October 9th, US History on November 6th, and World History on December 4th.</p>
<p>As far as I know, you can take up to 3 Subject Tests on the same date. I want to reschedule so I take both US History and World History on December 4th and have a second SAT on the November 6th. </p>
<p>I can change the November 6th date fine so I can do the SAT a second time, however when I try to add a new Subject Test is only has available rooms for January 2011 onwards, and when I try to change the test on the December 4th it keeps popping up with a message:</p>
<p>"It is not necessary to make changes to your Subject Tests. As long as you are registered for at least one Subject Test, you can finalize your Subject Test choices on the day of the test. Additional fees may apply. You will be billed after the test."</p>
<p>What does this mean? Does it mean when I arrive at the test center I can do both the World History and the US History without officially registering for US History in advance and I'll just be billed later?</p>
<p>Thanks :).</p>