פירוש על קידושין 46:5

The Talmud rejects the difficulty on R. Huna. An Israelite can never offer sacrifices himself. The laws of sacrificing in the Temple simply do not apply to him. However, a slave can accept a deed of manumission, just not his own. Thus these laws do apply to him, and therefore, he can appoint an agent to receive his own deed of manumission.