Question

what do you mean by the term to undo law

Answer 1

To repeal something — usually a law, ordinance or public policy — is to take it back. ... The verb repeal comes from the Anglo-French word repeler, “to call back.” Repeal is almost always used in the context of law: When a government decides to get rid of an ordinance or law, that ordinance or law is repealed.

Answer 2

It means to do amendment or abolition of any law