Highlight a character with a pendant on the map screen. Press Select + B until the pendant begins to flash in the "Spells/Attributes" portion of the screen. Then, press Select + A to display a prompt that allows the selection of the character to be revived. Choose a character, press A, then place that character at any location in the map that is under your control. Once revived, the character will have all the spells, attributes, and health present before his or her last battle.