Model elated over, for example, commission (8)
I believe the answer is:
delegate
'commission' is the definition.
(thesaurus)
'model elated over for example' is the wordplay.
'model' is an anagram indicator.
'over' indicates putting letters inside.
'for example' becomes 'eg' ('e.g.' can be a synonym of 'for example').
'elated' anagrammed gives 'delate'.
'delate' placed around 'eg' is 'DELEGATE'.
(Other definitions for delegate that I've seen before include "Transfer power to do something" , "Envoy" , "Mandate" , "Committee member" , "Pass down for action" .)