Most states require you to sit for all four parts at once. To retain credit for passing, you must pass two parts initially and obtain a minimum grade of 50% on parts failed. After this, you must sit for all parts failed but can now pass one part at a time, with a minimum again of 50% on part(s) failed. In most states, you are allowed 3 years (6 exams) to successfully complete the exam. If it is not passed within the 3 years, you will lose credit for parts passed and will need to start over. Unlike many other countries’ examinations, you will not be prohibited from sitting again.