By the mid-1970s, CTV had expanded its footprint across Canada, mostly by twinstick arrangements in smaller cities, and with CBC affiliates switching to CTV once the CBC opened its own stations or added rebroadcasters of nearby O&O stations. In a unique twist, the original Saskatchewan affiliate, CHAB/CHRE, was bought by the CBC in 1968 (and eventually changed its calls to CBKT, with the Regina station as the main station), allowing Regina's original station, CKCK-TV, to join CTV. Its attempt to expand to the United States ended when Buffalo's three network affiliates threatened legal action, forcing WNYP off the air.