Complex sentence: In 2005, the International Ice Hockey Federation attempted to alter the results of World Championship, awarding Canadians a bronze medal, but then it changed it's mind, and in September of 2005 the IIHF finally rejected Canada's appeal to be awarded 3rd place.
Split into simpler sentences: In 2005, the International Ice Hockey Federation attempted to alter the results of World Championship, awarding Canadians a bronze medal. But then it changed it's mind, and in September of 2005 IIHF finally rejected Canada appeal to be awarded the 3rd place.