Complete Shivah must be sat if one finds out within thirty days of the passing. This is the case even if everyone else in the family has already stood up from Shivah.

If the bad news arrives after thirty days, but before twelve (Jewish-lunar) months have elapsed, a truncated mourning period is observed. The mourner removes his/her shoes and sits on the ground; however this "shivah" only lasts for several minutes. If the deceased is a parent, then the mourner should also rend his/her garments.

After twelve months, this shortened shivah is only observed if the deceased is a parent.