What nation eventually aligned itself with the Triple Entente even though it started out being part of the Triple Alliance or Central Powers?
No country switched from the Triple Alliance to the Triple Entente. The Triple Entente consisted of the Russian Empire, France's Third Republic, and the United Kingdom (England & Ireland), supplemented by agreements with Portugal and Japan while the Triple Alliance was made up of Germany, Austria-Hungary, and Italy. Italy however, joined the Allied side during WW1.