Mitosis is the division of a cell nucleus in which the genome is copied and separated into two identical halves. Mitosis is normally followed by the division of the cell. Mitosis is divided into 4 phases. The first phase is prophase, followed by metaphase, then anaphase, and finally, telophase. Anaphase is the 3rd phase in mitosis.
During this phase, the chromosomes separate. The sister chromatids move to opposite poles of the parent cell with the help of spindle fibers that pull them apart. This happens with the shortening of the spindle fibers. One sister chromatid is present on one side of the pole, and the other moves to the opposite side of the pole. As the sister chromatids divide, centromere also divides. At the end of anaphase, each side of the pole has a complete set of chromosomes, making two chromosomes in one cell.
Actually, I'd consider this to be anaphase (if we don't count prometaphase). Interphase is definitely not part of the mitotic phases if you consult the cell cycle.