LEOSA Reform Act This bill revises provisions related to the carrying of concealed firearms by certain active duty and retired law enforcement officers. Specifically, the bill allows qualified active duty and retired law enforcement officers to carry concealed firearms, including magazines and ammunition, in school zones; on state, local, and private property that is otherwise open to the public; in national parks; and in certain federal facilities that are open to the public. Additionally, states may reduce the frequency (currently, once during the most recent 12-month period) with which a retired law enforcement officer must meet firearms training standards to be certified to carry a concealed firearm.