There are a lot of property tax fields. Which specific one are you not able to change? If it's not the Supporting Details situation that SteamTrain described, what topic or section of TurboTax are you in? What is the exact heading or title on the screen? What is the exact description of the field? If you are using forms mode in the desktop TurboTax software, what specific form and line number are you trying to change.
Many of the amounts in TurboTax are calculated, or they flow from another form, schedule, or worksheet. In order to change a calculated amount you have to go to the source form, schedule, or worksheet that feeds into it. If you are using forms mode, try using Data Source or QuickZoom to see where the amount comes from.
