Soon after accepting the Sabbath truth, Ellen White requested rebaptism—undoubtedly into the third angel's message. James White writes of this in Life Incidents, page 273, in connection with his presentation of Ellen White's visions: 1BIO 121.4
On receiving baptism at my hands, at an early period of her experience, as I raised her up out of the water, immediately she was in vision. 1BIO 121.5
This is the only reference to this step in her experience; the date of the rebaptism is not known. 1BIO 122.1