This summary is not the rule. The rule text controls.
When the court wants to reverse or make a big change to one of its own past decisions, all the judges have to talk it over together first. One judge or a small group can't just decide on their own to throw out old case law or change it in a major way.
This rule exists to keep the court's decisions steady and predictable. If judges could overturn past rulings without input from the full court, the law could shift unexpectedly depending on which judges heard a particular case. Requiring the whole court to weigh in helps make sure any major change in direction is carefully considered and reflects the court's shared judgment, not just one panel's view.
For people involved in a case, this means past court decisions carry real weight. You can generally rely on existing case law staying in place unless the full court agrees to change it.