22 June 2015
Your query is not clear. Under which law the company wants to change the method of depreciation; (a) companies act 2013 or (b) Income Tax Act.
(a) Schedule II of the Co's Act recognizes depreciation on the basis of useful life of the asset. Though the company may adopt a different useful life for a particular asset with proper disclosure but the method would be SLM. Earlier under Co's Act 1956 it was permissible to adopt different method of depreciation (either SLM or WDV) for different type of asset as per Sch XIV
(b) Income Tax Act prescribes only WDV method for all block of assets. However an electricity company may opt SLM method for calculation of depreciation, but such adopted method will be applicable for each block of asset.