When may a client state be absorbed?

[Bombax]

Hi folks, a quick question for you: what conditions need to pertain for a client state to be eligible for absorption by its 'owner' state? Is it just a matter of the number of turns, or do other conditions apply, before the local ruling class can be bought out?
TIA,
Jay

[Pocus]

automated, free, and total absorption is only done between 2 AIs.
Generous gifts of regions which are also one of your objectives or surrounded by at least 3 regions of you can happen if you have good relationships, low chance per turn.
for the rest, diplomatic interface and a lot of money!

[Bombax]

Thanks Pocus!