<p>i read somewhere that you can add a subject test on test day, is this true? and if so how do i do it?</p>
<p>Yes, this is completely true. On test day, just take the additional SAT II test (ie. sit in for the exam after having done your first one). The college board will bill you later. Remember, you can take up to three SAT II Subject Tests on any one test day, but you CANNOT take the SAT I Reasoning Test AND any Subject Tests on the same day.</p>
<p>can you switch exams on test day?</p>
<p>If by switching you understand taking Literature and Hebrew instead of Math L2 and Physics that you had choosen during your registration, yes, that's highly possible.</p>