The extension allows the taxpayer additional time to file the tax return. However, extensions do not extend the tax payment date, if any. That is, if for some reason you are unable to file your return by the due date, you may request an extension, but this does not allow you to make the late payment of the tax. To request the extension, you must first make the payment and complete Form SC 2644. You can find it at SURI. This form must be submitted in person at the Department of Treasury or at any of the Department's internal revenue offices. You can also mail it to the Department of Revenue or send it through SURI.