Step to get rid of a commotion (4)
I believe the answer is:
stir
'commotion' is the definition.
('stir' can be a synonym of 'commotion')
'step to get rid of a' is the wordplay.
'step' becomes 'stair' ('stair' can be a synonym of 'step').
'to get rid of' is a deletion indicator.
'stair' with 'a' removed is 'STIR'.
(Other definitions for stir that I've seen before include "Arouse; mix" , "Excitement" , "Mix round" , "Get moving" , "Agitate; wake from sleep" .)