>>48798831Latias can't actually "turn into" a human. She just refracts light off of her feathers to look human, she's still a Latias underneath. Latios is implied to be able to do the same thing or something similar.
>Latios has the ability to make others see an image of what it has seen or imagines in its head. This Pokémon is intelligent and understands human speech.They can't actually change, they just bend light or plant images in people's heads.