Transfer again, the donkey has one starting gallop now (8)
I believe the answer is:
reassign
'transfer' is the definition.
(I know that transfer can be written as reassign)
'again the donkey has one starting gallop now' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'the donkey' becomes 'ass' (ass is a term for a donkey).
'has' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'starting' indicates taking the first letters.
The first letters of 'gallop now' is 'gn'.
're'+'ass'+'i'+'gn'='REASSIGN'
(Other definitions for reassign that I've seen before include "Again appoint" , "put to further use" , "Freshly allocated" , "put in another place" , "Allocate again" .)