Change over hands, right to left (4)
I believe the answer is:
swap
'change over' is the definition.
(I've seen this before)
'hands right to left' is the wordplay.
'hands' becomes 'paws' ('paw' can be a synonym of 'hand').
'right to left' says the letters should be written backwards (letters written right to left).
'paws' back-to-front is 'SWAP'.
(Other definitions for swap that I've seen before include "Change over" , "Interchange" , "Exchange, barter" , "Exchange; hands back" , "Exchange goods" .)