Odinsgrandson gets it
Lord of Change can indeed summon his Bros, as he has access to Summon Lord of Change on his own Warscroll.
But, whilst if we accept that he has access to all Chaos Wizard Summon X spells, he can't actually cast any others, as they're not on his scroll.
I'd also like to introduce more correct rules reading....
Lord of Change can't actually summon his Bros, and the same goes for any other summoning spells unless specifically listed as one of the spells the Wizard knows, such as a Branchwraith, who comes with a summoning spell as their third.
Pour quoi?
Simple.
A Lord of Change is
Chaos; Wizard, these being two clearly defined key words upon its Warscroll.
Summon Lord of Change is known to
Chaos Wizards - presented as a single Key Word.
If we take it as two
separate key words, then all Wizards know all summoning spells all the time...