Complex sentence: CKOK disaffiliated from the CBC in 1977 and changed its call sign to CKOR-FM and in 1986 to its present call sign of CJMG.
Split into simpler sentences: CKOK disaffiliated from the CBC in 1977. CKOK-FM its call sign to CKOR-FM and in 1986 to its present call sign of CJMG.