Also what is the difference between SOA and CAS? Thank you!
SOA stands for "Society of Actuaries" and CAS stands for "Casualty Actuarial Society". CAS actuaries deal with property and casualty insurance, primarily, while SOA actuaries specialize in other fields like life, health and pensions. Both societies have a branch of risk management within the society.
Both societies sponsor the preliminary exams jointly (with a couple exceptions), but offer their own separate specialized exams that test knowledge specific to the appropriate type of business that each deals with.