Shopkeeper, for example, exchanges staff (9)
I believe the answer is:
tradesman
'shopkeeper for example' is the definition.
'exchanges staff' is the wordplay.
'exchanges' becomes 'trades' (trade is a kind of exchange).
'staff' becomes 'man' (manning is a kind of staffing**).
'trades'+'man'='TRADESMAN'
(Other definitions for tradesman that I've seen before include "I must sell stuff" , "Skilled worker; shopkeeper" , "Skilled hand" , "Buyer/seller of goods" , "Ten dramas for skilled workman" .)