Letting scourge return to fish (8)
I believe the answer is:
enabling
'letting' is the definition.
The answer and definition can be both related to change as well as being present participle verbs.
Perhaps there's an association between them I don't understand?
'scourge return to fish' is the wordplay.
'scourge' becomes 'bane' (synonyms).
'return' is a reversal indicator.
'to fish' becomes 'ling' (ling is a kind of fish).
'bane' written backwards gives 'enab'.
'enab'+'ling'='ENABLING'
Can you help me to learn more?
(Other definitions for enabling that I've seen before include "Authorising" , "Giving power to make possible" , "Empowering" , "Giving authority or means to do something" , "Being permissive" .)