SAT Test type change question?

<p>I signed up for the SATII world history but I just decided I want to take the SATI instead. It's no longer possible to change online. My question, is there a big possibility that I can change my test type on the Test day(Dec 4th)? Is it worth to prepare for? I want to know this because I also signed up for the ACT which I can prepare instead if it's not worth it.</p>