Generate changes for young person (8)
I believe the answer is:
teenager
'young person' is the definition.
(thesaurus)
'generate changes' is the wordplay.
'changes' indicates an anagram.
'generate' anagrammed gives 'TEENAGER'.
'for' is the link.
(Other definitions for teenager that I've seen before include "Youngster" , "Young person" , "one no longer twelve?" , "Adolescent" , "hormonal problem?" .)