Change, as the Constitution (5)
I believe the answer is:
amend
'change as the constitution' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for amend that I've seen before include "Make minor improvements to (a document)" , "Make minor improvements to (something)" , "Make small changes to" , "Correct error, make minor alteration as to writing" , "Alter in detail" .)