Hi Cece,
http://www.extension.umn.edu/projects/yardandgarden/ygbriefs /H101callacanna.html
"In the fall, dig up the rhizomes, cut the stems back to 2-3 inches, and let them dry. Leave them in a box in a cool part of the house where they will not freeze, such as a basement where the temperatures range between 40-50 degrees. Every few years, the rhizomes may be divided. When dividing, each piece must have an eye or growing point on it. Let the cut-up rhizomes dry for a few days before planting them."