Sometimes the noun is repeated for calling - אברהם אברהם (Abraham Abraham) משה משה (Moses Moses) or to teach a law - איש איש (any man).

And any place where the verb is mentioned alone at the beginning and afterwards is mentioned with a noun, at the beginning was an impersonal subject.

Leviticus 1:5 says,ושחט את בן הבקר לפני יהוה והקריבו בני אהרן הכהנים את הדם וזרקו את הדם על המזבח סביב אשר פתח אהל מועד (And he shall kill the bullock before the LORD; and Aaron's sons, the priests, shall present the blood, and dash the blood round about against the altar that is at the door of the tent of meeting), in which the verb is mentioned alone at the beginning and afterwards the verb is mentioned with a noun. According to Rule 149, this means that the noun at the beginning was an impersonal subject, implying that the killing of the bullock does not have to be done by a priest³²⁸.

footnotes: ³²⁸ Malbim, HaTorah v’HaMitzvah Vayikra 35.