Tressa - you need to see the legal documents creating the corporation, and by-laws outlining the rules for the Board.
Whoever did the legal work to put your banks under one charter (that's what they did, right?) should be able to help you with that. Most likely the by-laws for the 'surviving charter' - the one who's TR and charter number you'll continue using - will be the one that rules and you won't need a new one. Nor will you need a new board of directors. If management wants to change the makeup of the board, they'll need by-law and/or shareholder authority to do so.
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Opinions my own.