Amendment

noun

1. An alteration or change for the better; correction of a fault or of faults; reformation of life by quitting vices.
2. In public bodies, any alteration made or proposed to be made in a bill or motion that adds, changes, substitutes, or omits.
3. Correction of an error in a writ or process.
4. An addition to and/or alteration to the Constitution.

   "The First Amendment guarantees freedom of religion, speech, press, assembly, and petition."

5. That which is added; that which is used to increase or supplement something.

   "a soil amendment"