Straight line depreciation is correct for residential rental real estate. I am assuming you are referring to 2 rental properties, and not improvements or other personal property. Thus, 27.5 years straight line is appropriate, please see: IRS Publication 527. Bonus depreciation is also not applicable to 27.5 year residential rental property, but certain improvements depreciated over shorter periods would have allowed this (in year of purchase or via accounting method change).
A 3115 should have been filed last year. Adjusting the prior year depreciation without taking any expense will not correct the error. As well, since there is no bonus depreciation allowed for 27.5 year property, manipulating that figure was also not correct.
You will need to file a 3115 for 2024, since the deadline to file the 3115 for 2023 has passed. You can calculate the difference in depreciation and prepare the 3115 in a Desktop version of TurboTax.
