Shari Redstone on Tuesday said amending CBS Corp. bylaws amid the ongoing struggle for control of the media giant was necessary to prevent the permanent diminution of her voting power.

In a new lawsuit, Redstone and her family’s National Amusements Inc. holding company challenged several “unsupported, false and pretextual” assertions CBS has levied in recent weeks, and sought to paint a far different picture of the legal saga, which is now before a Delaware Chancery Court judge.