Reduce useful life of assets

Asset life is 10 year in system (purchased date is 26.02.2010) Capitalized on 26.02.2010 First acquisition on 26.02.2010 Acquisition year 2009 011 deperication is based on asset useful life and deperication is posed upto march 2018, now we want to change the asset life is of 8 years instead of 10 years. what is the solution?
dep-calc.jpg
pls explain