  In a recent paper [Phys. Rev. E 67, 026204 (2003)], Rotter calculates the
geometric phases that are picked up by the eigenvectors of a two-state quantum
system when an exceptional point is encircled. In addition to the geometric
phases observed by Dembowski et al. in a microwave cavity experiment [Phys.
Rev. Lett. 86, 787 (2001)], she finds a phase factor of i. We show that Rotters
results are inconsistent.
