A couple of daughters have terrible tape changed (7)
I believe the answer is:
adapted
'changed' is the definition.
(adapting is a kind of changing)
'a couple of daughters have terrible tape' is the wordplay.
'couple of' shows that letters should be duplicated.
'daughters' becomes 'd' (genealogical abbreviation for daughters).
'have' is an insertion indicator.
'terrible' indicates anagramming the letters.
'd' doubled is 'dd'.
'tape' anagrammed gives 'apte'.
'dd' going around 'apte' is 'dapted'.
'a'+'dapted'='ADAPTED'
(Other definitions for adapted that I've seen before include "made to fit" , "Date-pad (anag.)" , "Altered" , "Changed to suit anoter purpose" , "Made suitable for new purpose" .)