Leviticus 5:7 WEB

⁵  It shall be, when he is guilty of one of these, he shall confess that in which he has sinned:

⁶  and he shall bring his trespass offering to Yahweh for his sin which he has sinned, a female from the flock, a lamb or a goat, for a sin offering; and the priest shall make atonement for him concerning his sin.

⁷  ''If he can't afford a lamb, then he shall bring his trespass offering for that in which he has sinned, two turtledoves, or two young pigeons, to Yahweh; one for a sin offering, and the other for a burnt offering.

⁸  He shall bring them to the priest, who shall first offer the one which is for the sin offering, and wring off its head from its neck, but shall not sever it completely.

⁹  He shall sprinkle some of the blood of the sin offering on the side of the altar; and the rest of the blood shall be drained out at the base of the altar. It is a sin offering.