Changes make commercial suitable to use at centre (6)
I believe the answer is:
adapts
'changes' is the definition.
(adapting is a kind of changing)
'commercial suitable to use at centre' is the wordplay.
'commercial' becomes 'ad' (abbreviation for advertisement).
'suitable' becomes 'apt' (apt means appropriate or fitting).
'at centre' indicates the central letters.
The centre of 'use' is 's'.
'ad'+'apt'+'s'='ADAPTS'
'make' acts as a link.
(Other definitions for adapts that I've seen before include "Modifies for a new use" , "Alters for another use" , "Alters to fit" , "Changes to suit new circumstances" , "Adjusts for a new use" .)