Anaphase is the 'A' in "PMAT." The 'A' in Anaphase stands for "Apart." The Chromosomes are pulled apart by the 2 spindle fibers that are on either side of them. when they are seperated they are called Chromotids The spindle fibers then pull the Chromotids to the oppisite ends of the cell. The Chromotids are now called Chromosomes again.
This diagram shows the step located within Mitosis called Anaphase.