1,326. Notification Before Yom Tov

206:6 If one received timely notification of a death on a Shabbos that was also erev yom tov,  since he observed private mourning, the arrival of yom tov cancels the rest of shiva.

206:7 If a person receives delayed notification of a death on Shabbos or yom tov, he doesn’t observe any form of mourning; even private things are permitted. After Shabbos or yom tov, he observes one hour of mourning and that is sufficient.