Party for levelling out class differences? (6,7)

'party' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'levelling out class differences?' is the wordplay.
I cannot quite understand how this works, but
'levelling' could be 'evening' ('even' can be a synonym of 'level') and 'evening' is found within the answer.
'class' could be 'social' (synonyms) and 'social' is found within the answer.
No letters remain.
This explanation may well be incorrect...

'for' is the link.

Can you help me to learn more?