Score cannot change, only partially (5)
I believe the answer is:
notch
'score' is the definition.
(thesaurus)
'cannot change only partially' is the wordplay.
'partially' says the answer is hidden in the clue.
'NOTCH' can be found hidden inside 'cannot change only'.
(Other definitions for notch that I've seen before include "Small V-shaped cut or indentation" , "small score?" , "Dent" , "Salad plant, garnish" , "V-shaped incision" .)