The simple holo on Leia's desk gave her the answer; a candid picture of a young man– Rey's ghost– trying to pull something out of Leia's hands. When Rey asks Leia about it, the general wipes away tears.
So here she is, alone in the forest, trying to meditate the way Master Luke taught her, trying to call her ghost to her.
When she opens her eyes, he is there.
She says his name and his smile falters. She corrects herself and his hand brushes over her cheek.
"You look so much like your mother," he says, "My eyes, though."
There are so many questions bubbling up in her mind. But she smiles at her ghost, her father, the one the old rebels called 'Starkiller', the one who's legacy she'd try to uphold.
"Father," she says.
(He teaches her force lightning)