Psychic Transfer

Sorcery

If the difference between your life total and target player's life total is 5 or less, exchange life totals with that player.

2008-08-01:
If one of the players has a negative life total, you use their actual life total for determining the difference. If that difference is five or less, then the other player receives the negative life total.
2011-01-01:
If an effect says that a player can’t lose life, that player can’t exchange life totals with a player who has a lower life total; in that case, the exchange won’t happen.