Swap some coins (6)
I believe the answer is:
change
I believe this is a double definition.
'swap' is the first definition.
(I know that swap is a kind of change)
'some coins' is the second definition.
(change can mean coins)
(Other definitions for change that I've seen before include "Novelty" , "Replace" , "Coins of low value" , "It's said to be as good as a rest" , "Make different; coins" .)