Swivel to act like a ball (4,5)
I believe the answer is:
turn round
'swivel' is the definition.
(thesaurus)
'act like a ball' is the wordplay.
'act' becomes 'turn' (theatre).
'like a ball' becomes 'round' (I've seen this in another clue).
'turn'+'round'='TURN ROUND'
'to' is the link.
(Other definitions for turn round that I've seen before include "having to unload and reload" , "Rotate" , "In reversal of fortunes" , "show them one's back!" , "Complete reversal" .)