On January 1, 2014, Klinefelter Company purchased a building for $520,000. The building had an estimated life of 20 years and an estimated residual value of $20,000. The company has been depreciating the building using straight-line depreciation. At the beginning of 2020, the following independent situations occur:
a. The company estimates that the building has a remaining life of 10 years (for a total of 16 years).
b. The company changes to the sum-of-the-years’-digits method.
c. The company discovers that it had ignored the estimated residual value in the computation of the annual depreciation each year.

Required:
For each of the independent situations, prepare all journal entries related to the building for 2020. Ignore income taxes.