Original sentence: The Confederate States of America (CSA, also known as the Confederacy) was the federation initially formed in 1861 by seven southern slave states (South Carolina, Mississippi, Florida, Alabama, Georgia, , Louisiana, and Texas) that seceded from the United States
Edited sentence: The Confederate States of America (CSA, also known as the Confederacy) was the federation initially formed in 1861 by seven southern slave states (South Carolina, Mississippi, Florida, Alabama, Georgia, , Louisiana, and Texas) that declared their secession from the United States