One thing to note, however, is that whether your Arlinn is a humble Kord or has become Embraced by the Moon, she’s still the same permanent, as nothing has caused her to enter or leave the battlefield. Things that change: her name and abilities. Things that stay the same: her converted mana cost (a change from previous rules), her loyalty, her colors (as indicated by the nifty little color indicator dot), her planeswalker type (still Arlinn, so don’t cast a second one), and any other ongoing effects on her; meaning she’s still counted as having activated a loyalty ability that turn. Most commonly, if you activate her front face’s 0 ability and transform her, you cannot activate any of her back face abilities that turn (and good thing, too; she’d be quite overpowered if you could!).
Today’s Rules Tip written by Jen Wong