So I was admitted into UCSC and UCI but I’m unable to take one of the two ap Exam that I indicated I would take on my application. If I inform UCSC and UCI about not taking it, will my admissions be revoked?
No, AP exams are not considered in admissions decisions. All you will loose is the possible college credit if you do not take exam. Read over your provisional admission contract and no where does it say anything about AP exams. Dropping AP classes, then that is another issue.