In broadcasting, sister stations or sister channels are radio or television stations operated by the same company, either by direct ownership or through a management agreement. Radio sister stations will often have different formats, and sometimes one station is on the AM band while another is on the FM band. Conversely, several types of sister-station relationships exist in television; stations in the same city will usually be affiliated with different television networks (often one with a major network and the other with a secondary network), and may occasionally shift television programs between each other when local events require one station to interrupt its network feed.