Make minor improvements to (5)
I believe the answer is:
amend
'make minor improvements to' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for amend that I've seen before include "Correct or alter to improve" , "Modify - edit" , "Make small changes to" , "Modify, correct" , "Correct error, make minor alteration as to writing" .)