Get better workers in a time leading to change (9)
I believe the answer is:
Here is my best explanation:
'change' is the definition.
(amendment is a kind of change)
'get better workers in a time leading' is the wordplay.
'get better' becomes 'mend' ('mend' can be a synonym of 'get better'**).
'workers' becomes 'men' (man is a kind of worker).
'in' indicates putting letters inside.
'leading' indicates taking the first letters.
The initial letter of 'time' is 't'.
'mendmen' placed into 'at' is 'AMENDMENT'.
'to' is the link.
(Other definitions for amendment that I've seen before include "correction", "Minor improvement", "Alteration made in a formal document", "Correction", "a bit of a change!", "Addition or alteration, to a motion or official document, say", "Corrective treatment", "change for the better", "the fifth one benefiting Uncle Sam's defendants?" and "A qualification".)