Answer: supplied war materials to Allied nations without a declaration of war
Step-by-step explanation:
The Lend-Lease Act, was approved in 1941 and it's an Act that gave President Roosevelt authority to supply things like ammunition, foods, airplanes, tanks, trucks, etc to their allies during the war in Europe while the country was still neutral and maintaining its position of neutrality.
This Act changed changed the policy of the United States toward the nations that are involved in World War II because supplied war materials to Allied nations without a declaration of war.