How did Roosevelt's lend lease act shift US foreign policy away from isolationism??

Roosevelt's Lend Lease Act actually was in regards to the internal security of the United States of America. United States of America did lend ships and other war equipments to countries like France, United Kingdom, China etc in favor of leases on the army bases and ports of Allied territories during the time of war. No money was charged by United states, but after the war was over equipments such as ships were needed to be returned.