Thurber Co purchased equipment for 710000 which was estimated to have a useful life of 10 years with a salvage value of 10000 at the end of that time. Depreciation has been entered for 7 years on a straight line basis. In 2013 It is determined that the total estimated life should be 15 years with a salvage value of 4000 at the end of that time. Prepare the entry (if any) to correct the prior years depreciation