Amendment that does what Canute demonstrably couldn’t? (4)
I believe the answer is:
edit
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for edit that I've seen before include "Revise - expurgate" , "Check text for publication" , "Revise text" , "Alter text" , "Make textual changes" .)