Pharaoh is not the name of a person, but was the title borne by all the Egyptian monarchs.
Related Commentaries of Genesis 12:14
Genesis 12:14-15
14 And it came to pass, that, when Abram was come into Egypt, the Egyptians beheld the woman that she was very fair.
15 The princes also of Pharaoh saw her, and commended her before Pharaoh: and the woman was taken into Pharaoh's house.