Changed a dressing, upsetting Edward (7)
I believe the answer is:
adapted
'changed' is the definition.
(adapting is a kind of changing)
'a dressing upsetting edward' is the wordplay.
'dressing' becomes 'pad' (type of medical dressing).
'upsetting' shows that the letters should be reversed in order.
'edward' becomes 'ted'.
'pad' backwards is 'dap'.
'a'+'dap'+'ted'='ADAPTED'
(Other definitions for adapted that I've seen before include "Changed to suit another purpose" , "Changed for a particular purpose" , "Turned to new purpose" , "made to fit" , "Altered" .)