All made the day before Roy changed quarters (8)
I believe the answer is:
everyone
'all' is the definition.
(thesaurus)
'the day before roy changed quarters' is the wordplay.
'the day before' becomes 'eve' (I've seen this before).
'changed' is an anagram indicator.
'quarters' becomes 'ne'.
'roy' anagrammed gives 'ryo'.
'eve'+'ryo'+'ne'='EVERYONE'
'made' acts as a link.
(Other definitions for everyone that I've seen before include "Uncle Tom Cobleigh and all" , "All the people" , "Entire group" , "All and sundry" , "All without exception" .)