No it doesn't replace dexterity by charisma. It's in help file. You dodge according to your charisma while it's higher then your dexterity. So if they maledicted only your charisma you just started to dodge like anyone else by dexterity. It's awsome edge. The best that bard can get. The only thing that is VERY odd for me is it's price. It's so DAMN CHEAP!. I got swashbuckler somethere around 25 rank. Al I had at moment is about 2300 Imm exp, 1 PK and almost zero exploration. And I got erode confidence as well.