Leviticus 5:10, 12, 18

And he shall offer the second as a burnt offering according to the prescribed manner. So the priest shall make atonement on his behalf for his sin which he has committed, and it shall be forgiven him.

Then he shall bring it to the priest, and the priest shall take his handful of it as a memorial portion, and burn it on the altar according to the offerings made by fire to the LORD. It is a sin offering.

And he shall bring to the priest a ram without blemish from the flock, with your valuation, as a trespass offering. So the priest shall make atonement for him regarding his ignorance in which he erred and did not know it, and it shall be forgiven him.