Change paws over (4)
I believe the answer is:
swap
'change' is the definition.
(I know this)
'paws over' is the wordplay.
'over' says the letters should be written in reverse.
'paws' reversed gives 'SWAP'.
(Other definitions for swap that I've seen before include "Interchange" , "Exchange, substitute" , "Exchange; hands back" , "Fifty-fifty odds" , "Switch" .)