Leviticus 27:9-11

The Voice

⁹ Whenever someone vows to give an animal that is acceptable as an offering to Me, then that animal is sacred and is the property of the sanctuary. ¹⁰ Whoever makes the vow should not switch one animal for another, a good animal for a bad, or vice versa. If someone does switch one for another, then both animals are considered sacred. ¹¹ But if the vow involves an animal that is impure and not acceptable as an offering to Me, he needs to bring the animal before the priest.