How does conversion change the subject and predicate of a categorical proposition?

In syllogistic or traditional logic, conversion is the process of interchanging the subject and predicate of a categorical proposition to form a new statement. The validity of this inference depends on the form of the proposition (A, E, I, or O):21

• Simple Conversion (simpliciter): Propositions of forms E (universal negative) and I (particular affirmative) can be converted by simply swapping the subject and predicate while maintaining logical equivalence. For example, "No men are immortal" converts to "No immortals are men," and "Some man is mortal" converts to "Some mortal is man".21
• Accidental Conversion (per accidens): Propositions of form A (universal affirmative) cannot be converted simply because the resulting statement is not necessarily true. Instead, they are converted by interchanging the terms and weakening the universal quantifier to a particular quantifier ("some"). Thus, "Every $\beta$ is an $\alpha$" converts to "Some $\alpha$ is a $\beta$".13
• No Conversion: Propositions of form O (particular negative) cannot be validly converted; interchanging the terms does not preserve the truth of the original statement.13