When Higuchi died, the original death note was in hands of Light, so he becomes the owner again. After L dies, and Mello exchanges that death note for Sayu, how did Kal Snyder end up as the owner, if Light did not forfeit ownership of his death note between that time?
After Higuchi died, the Death Note was kept by the investigator so Light couldn't use the death note. After L died, the book was kept by Soichiro Yagami for quite a long time. At that time, Light had lost his possession of Death Note either by giving it to his father or by not using it for a long time.
When Soichiro gave the Death Note to the guy who kidnapped Sayu, he gave him the possession as well. At last, this guy lost his possession of Death Note after he died in a plane. The one who first touched the Death Note after that was Kal Snyder.