Half of them come before the finish to make a repair (5)
I believe the answer is:
emend
'repair' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
'half of them come before the finish to make a' is the wordplay.
I cannot really see how this works, but
'them' could be 'em' (abbreviation) and 'em' is found within the answer.
'finish' could be 'end' (synonyms) and 'end' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for emend that I've seen before include "Rectify" , "Revise (a text) (E, not A)" , "Improve (writing)" , "Alter to improve (text)" , "Modify" .)