Formal/Legal:
* Alteration: This emphasizes a change made to something, usually a document or text.
* Modification: Similar to alteration, but often implies a more significant change.
* Revision: A more formal word for making changes to improve something.
* Correction: Used when the amendment fixes an error.
* Addition: This refers to something being added to the original text or document.
Informal:
* Change: This is a general term for any kind of adjustment or improvement.
* Improvement: This implies that the amendment makes something better.
* Refinement: This suggests a subtle or minor change that enhances something.
Other:
* Emending: A more formal and literary synonym for amending.
* Rectification: This is used when the amendment fixes a problem or mistake.
The best synonym to use will depend on the specific situation and the intended meaning.