Cavaliere dell'Anima di Drago

If Dragonsoul Knight gains flying after blockers have been declared, it won’t cause those blocks to change.

When Dragonsoul Knight’s activated ability resolves, Dragonsoul Knight will gain flying and trample in addition to its other abilities. However, becoming a Dragon will make it lose all other creature types. It will no longer be a Human or a Knight.

You can activate Dragonsoul Knight’s ability more than once during a turn. The second time it resolves, it will probably have no visible effect other than giving Dragonsoul Knight another +5/+3.