In season 4 of “The Office,” Karen becomes manager of a rival Dunder Mifflin branch in Utica, New York. The development is revealed in the episode “Branch Wars,” after Karen has moved on from the Scranton office and her relationship with Jim.
Karen Filippelli had previously worked as a salesperson in Scranton and dated Jim Halpert. After Jim ended their relationship, she pursued a management position and became regional manager of the Utica branch. Her new role makes Utica a direct rival to Scranton in the episode's workplace conflict.
Michael Scott and Dwight Schrute travel to Utica after Karen attempts to recruit Stanley Hudson. The trip becomes a comic “branch war,” with Michael trying to undermine Karen's office while Jim, who knows her best, is dragged into the mission. Utica is a real city in central New York, roughly between Syracuse and Albany.