Notices about suitable changes (6)
I believe the answer is:
adapts
'changes' is the definition.
(adapting is a kind of changing)
'notices about suitable' is the wordplay.
'notices' becomes 'ads' (advertisements).
'about' means one lot of letters goes inside another.
'suitable' becomes 'apt' (apt means appropriate or fitting).
'ads' enclosing 'apt' is 'ADAPTS'.
(Other definitions for adapts that I've seen before include "Modifies or changes for another use" , "Modifies for a new use" , "Converts to another use, say novel to stage" , "Alters to fit" , "fashions" .)