"Here, madam," squeaked the house-elf, and Harry saw two leather boxes, one on top of the other, moving across the room as if of their own volition, though he knew the tiny elf was holding them over her head as she wended her way between tables, pouffes, and footstools.
There are no more uses of "volition" in the book.
Show samples from other sources
She left the company of her own volition.
Without volition I leaned toward her, as a tree is swayed by the wind.