What is the accounting treatment if management increase asset life depreciation after some years?

For example: An asset is puchesed or date of operation is1st January2013 and useful life is5 years. That means the last date of depreciation is31st December2017. The asset's acquisition cost $100, accumulated depreciation is $20 and carrying value $80. 

Now31st December2014, management decided that the asset's useful life will be increased from5years to 7 years. So right now the remaining useful life will be 5 years and remaining and carrying value is $80. $80 will be depreciating over the remaining5 years which is per year $16.