You *NEED* to seek professional help for this. Especially if your state taxes personal income. One reason (of many) is because a SCH C property is depreciated over 39 years, while a SCH E property is depreciated over 27.5 years. You can "NOT" make the switch correctly with the TurboTax program. You *NEED* (aka *REQUIRE*) professional help to get this done correctly. Additionally, you will have to take note of depreciation taken while it was a SCH C property, as even with professional help prior SCH C depreciation can NOT be tracked or accounted for on the SCH E in the way required. This will matter big time in the future when you sell or otherwise dispose of the property.
