By simply removing what is erroneous, corrupt, superfluous, faulty, and the like.
By supplying deficiencies.
By substituting something else in the place of what is removed; to rectify. Mar not the thing that can not be amended. (Shak) An instant emergency, granting no possibility for revision, or opening for amended thought. (De Quincey) We shall cheer her sorrows, and amend her blood, by wedding her to a norman. (Sir W. Scott) to amend a bill, to make some change in the details or provisions of a bill or measure while on its passage, professedly for its improvement.
These words agree in the idea of bringing things into a more perfect state. We correct (literally, make straight) when we conform things to some standard or rule; as, to correct proof sheets. We amend by removing blemishes, faults, or errors, and thus rendering a thing more a nearly perfect; as, to amend our ways, to amend a text, the draft of a bill, etc. Emend is only another form of amend, and is applied chiefly to editions of books, etc. To reform is literally to form over again, or put into a new and better form; as, to reform one's life. To rectify is to make right; as, to rectify a mistake, to rectify abuses, inadvertencies, etc.