Can I change accounting methods to a Safe Harbor expense after taking depecriation for several years using form 3315?

I have a rental property that was rented 50% and replaced the water heater 3 years ago. I started to depreciate the water heater each year. This year I changed the rental property to 100% rental and realized the lifetime depreciation for a water heater is 27.5 years (ugh).

 

Can I use Form 3115 - Application for Change in Accounting Method, to change from depreciation to taking a one-time Safe Harbor expense?

 

I have seen references to doing this but have not found an actual example or confirmation that this is true.

 

Form 3115 also indicates that if there is a change in use for the asset, you don't need to file 3115 for a change in Accounting Methods.

 

Or can you only elect Safe Harbor or De Minimis the year the expense was incurred?