Reincarnation was the belief that someone's spirit was reborn in a new body after the death of the old body.
The Kronteps believed in a form of reincarnation: after a brave death, their spirit was supposed to return to life, to be born in a more noble warrior, until in the final stage a Krontep would become a king and, eventually, reach the home of the gods. (TV: Mindwarp)
After his encounter with The Book of the Old Time, the Seventh Doctor began to suspect that before regeneration, there had been reincarnation. (PROSE: Cat's Cradle: Time's Crucible) The Doctor later discovered that he might have been the genetic reincarnation of the Other. (PROSE: Lungbarrow)
The Vandosians used quantum runes to determine when and where a person was reincarnated. Through this, they believed that in 1979, Shogalath had returned in the body of the human, Phil Tyson. Under Vandosian law, a reincarnation was to be held accountable for the previous life's crimes. (COMIC: Mr Nobody)