Feet up, for a change (4)
I believe the answer is:
swap
'a change' is the definition.
(thesaurus)
'feet up' is the wordplay.
'feet' becomes 'paws' (paw is a kind of foot).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'paws' written backwards gives 'SWAP'.
'for' acts as a link.
(Other definitions for swap that I've seen before include "Switch" , "Exchange; hands back" , "Exchange, substitute" , "Interchange" , "Substitute' feet backwards" .)