Ynglinga saga

We shall now come to instances in which the person who is changed has a double shape, and the soul animates one after the other.

The Ynglinga Saga says of Odin that he changed form.

The bodies lay as though sleeping or dead, but he was a bird or a beast, a fish or a woman, and went in a twinkling to far distant lands, doing his own and other people's business.

In like manner, the Danish king Harald sent a warlock to Iceland in the form of a whale, whilst his body lay stiff and stark at home.