- You may be looking for fal-tor-voh.
The fal-tor-pan was a Vulcan ritual designed to reunite a Vulcan's katra with his or her body. It literally meant "re-fusion" in the Vulcan language. A mediating Vulcan, using his or her inherent telepathic abilities, transferred the katra into the original body. The ritual was considered very dangerous, both to the recovering deceased person, and to the keeper of the katra. For this reason, it was almost never performed, and, in 2285, it was in doubt that the ritual had ever been performed at all.
The fal-tor-pan was performed by High Priestess T'Lar on Captain Spock in 2285 after he was recovered from the Genesis Planet by Admiral Kirk. Prior to Spock's death during the Battle of the Mutara Nebula, he had transferred his katra into Doctor Leonard McCoy, but, after the Genesis effect revived Spock's body, the Enterprise senior staff took McCoy and the resurrected Spock to Mount Seleya on Vulcan, where Sarek requested that fal-tor-pan be performed to restore Spock's katra to his body. (Star Trek III: The Search for Spock) Despite the implied danger, McCoy came through the ritual unharmed, and, after a period of temporary amnesia as his knowledge returned to him, Spock soon returned to himself. (Star Trek IV: The Voyage Home)
In the novel More Beautiful Than Death- set in the Alternate reality created by Nero- T'Pring's counterpart attempts to perform the fal-tor-pan to transfer the katra of Stonn from a Katric ark into Spock's body, but Sarek, Uhura and Kirk are able to stop her.