Full Idea
Qualitative change is seen as either (i) 'Presentism' - 'a is F now', or (ii) 'relational properties' - 'a is F-at-t', or (iii) 'temporal parts' - 'a-at-t is F', or (iv) 'adverbial' - 'a is-a-t F'.
Clarification
a is an object, t is a time, and F is a property or predicate
Gist of Idea
Four theories of qualitative change are 'a is F now', or 'a is F-at-t', or 'a-at-t is F', or 'a is-at-t F'
Source
report of E.J. Lowe (A Survey of Metaphysics [2002], p.44) by PG - Db (ideas)
Book Reference
Lowe,E.J.: 'A Survey of Metaphysics' [OUP 2002], p.44
A Reaction
The traditional view would let a stay the same over time, and change its property (ii). Lewis favours (iii). My suspicion is that thinking collapses if you abandon the tradtional view.