The company holds a patent on a toy which is amortized during year-end adjustments. The $25,000 patent's economic life is 10 years although the legal life is 20 years.

My adjusting entry:

Patent Amortization 2,500
Patent 2,500

My reversing entry:

Patent 2500
Patent Amortization 2500

No, you don't do a reversing entry for amortising/depreciating anything.