Adam Clarke on Genesis 45:22

Changes of raiment - It is a common custom with all the Asiatic sovereigns to give both garments and money to ambassadors and persons of distinction, whom they particularly wish to honor. Hence they keep in their wardrobes several hundred changes of raiment, ready made up for presents of this kind. That such were given by way of reward and honor, see Jdg 14:12, Jdg 14:19; Rev 6:11. At the close of a feast the Hindoos, among other presents to the guests, commonly give new garments. A Hindoo garment is merely a piece of cloth, requiring no work of the tailor - Ward.