Invalidate

[Sarah]

To render invalid; to weaken or lessen the force of; to destroythe authority of; to render of no force or effect; to overthrow; as,to invalidate an agreement or argument.

[Dianne]

to officially stop a document, ticket, law, etc. being legally or officially acceptable

[Mary Mallozziberg]

Make (an argument, statement, or theory) unsound or erroneous.