Complex sentence: The Argonauts then announced they would move to an expanded and renovated BMO Field in 2016; once the move is complete, the movable seating at Rogers Centre will be permanently locked into its baseball configuration.
Split into simpler sentences: The Argonauts then announced they would move to an expanded and renovated BMO Field in 2016. With the move now complete, the movable seating at Rogers Centre will be permanently locked into its baseball configuration.