You said it! In the end, demand always changes (6)
I believe the answer is:
amends
'changes' is the definition.
(amending is a kind of changing)
'you said it in the end demand always' is the wordplay.
'you said it' becomes 'amen' (I've seen this in another clue).
'in the end' says to take the final letters.
The last letters of 'demand always' are 'ds'.
'amen'+'ds'='AMENDS'
(Other definitions for amends that I've seen before include "Make these to atone for injuries or loss caused" , "Make these to right wrong" , "Changes for the better" , "Fixes" , "Makes changes, to a text say" .)