diarch_changed_own_contract_effect

diarch_changed_own_contract_effect = {
	if = {
		limit = { always = scope:diarch }
		if = {
			limit = { scope:recipient = { is_diarch_of_target = scope:puppet_or_actor } }
			scope:puppet_or_actor = { save_scope_as = liege }
			scope:recipient = { save_scope_as = diarch }
		}
		else_if = {
			limit = { scope:puppet_or_actor = { is_diarch_of_target = scope:recipient } }
			scope:recipient = { save_scope_as = liege }
			scope:puppet_or_actor = { save_scope_as = diarch }
		}
		if = {
			limit = { exists = scope:diarch }
			scope:diarch = {
				custom_tooltip = liege_modify_vassal_contract_interaction.tt.diarch_powers_used
				# Co-rulers lose a fair bit less & can change multiple times.
				if = {
					limit = {
						diarch ?= scope:liege
						has_diarchy_active_parameter = diarchy_is_co_rulership
					}
					add_opinion = {
						target = scope:liege
						modifier = abused_position_of_trust_opinion
						opinion = -10
					}
				}
				# Everyone else loses much more.
				else = {
					add_to_variable_list = {
						name = diarch_contract_rights_used_list
						target = scope:liege
					}
					add_opinion = {
						target = scope:liege
						modifier = abused_position_of_trust_opinion
						opinion = -40
					}
				}
			}
		}
	}
}

As written in game/common/scripted_effects/00_diarchy_scripted_effects.txt.