Try to enter your property tax and mortgage interest in the Schedule E for the Rental and remove it from the Deductions & Credits section.
TurboTax will then automatically calculate how much of this taxes and interest can be deducted for your rental. It will also add any remaining interest to Schedule A. The total of the two should equal your 1098.
example, when TurboTax asks Was This Property Rented for All of 2016? and
you answer No, you'll be prompted to enter days of rental use and
days of personal use. As you continue in the rental section, you'll enter the
mortgage interest and property tax for the home. Later, when you work on your
personal Deductions & Credits, TurboTax will remind you not to enter
property taxes or mortgage interest that have already been included with your
rental property. (See the attached screenshot below. Click to enlarge.)
Also, in the Do Any of these Situations Apply screen, check "I converted this property from rental to personal use in 2016". (See the attached screenshot below. Click to enlarge.)
Next year, there is nothing you need to do if you haven't received income for the year.
If and when you sell it, then at that point, the status of the house will be determined either personal or rental/investment property. The IRS would then tax the gain/loss accordingly.
So there's nothing to do to convert it, you'll just simply no longer file the Schedule E's with your return since there is no rental income. If you depreciated the property, then you'll want to keep a record of that total amount, as it will be needed to adjust the cost basis of the house for taxes, if/when you do sell.