The priest is to offer one as a sin offeringa and the other as a burnt offering to make atonement for the Nazirite because they sinned by being in the presence of the dead body. That same day they are to consecrate their head again.
and the priest shall offer one for a sin offering and the other for a burnt offering, and make atonement for him, because he sinned by reason of the dead body. And he shall consecrate his head that same day
The priest will offer one of the birds for a sin offering and the other for a burnt offering. In this way, he will purify them from the guilt they incurred through contact with the dead body. Then they must reaffirm their commitment and let their hair begin to grow again.