invite_special_guest_to_activity_effect

invite_special_guest_to_activity_effect = {
	if = {
		limit = {
			exists = var:special_guest
		}

		var:special_guest = {
			save_scope_as = the_special_guest
		}

		save_scope_as = sender

		scope:the_special_guest = {
			add_to_activity = scope:activity

			set_variable = {
				name = booked_for_a_party
				value = scope:sender
				days = 20
			}
		}
		
		remove_variable = special_guest
	}
}

As written in game/common/scripted_effects/03_dlc_fp2_scripted_effects.txt.