1 After six days Jesus took with him Peter, James and John the brother of James, and led them up a high mountain by themselves. 2 There he was transfigured before them. His face shone like the sun, and his clothes became as white as the light. 3 Just then there appeared before them Moses and Elijah, talking with Jesus." (Matthew 17:1-2 NIV1984)
The word "transfiguration" actually from the Greek Bible is metamorphosis, indicating a change in the being, like when a worm turns intoi a butterfly.
Jesus changing.
He had been possessed by the spirit of AElijah, but here, Eljah is emptied out and walks away with Moses:
Matt. 17:2
And was transfigured, (in the original Greek: metamorphized, as he emptied himself of the Holy Ghost of Elijah in the ritual of Kenosis, or emptying, the relinquishment of all divine attributes and return to a human being again: [Matt 28:19]),
right before them, (the soul of Elijah, now departing from him: [Ps 22:1/Matt 27:46]):
and his face did shine as the sun, (as had the face of Moses in the presence of God, on the mountain),
and his raiment was white as the light [Rev 1:13-15].
Later, at the bottom of the mount, Jesus tells his apostles that The Elijah had, indeed, come, been mistreated, but now was gone.