Va. Code Ann. § 58.1-933

Any qualified heir is required to notify the Commissioner, on a form prescribed by the Commissioner, of any disposition or change in use of the property and pay any additional Virginia estate tax resulting from such disposition or change, within six months of such disposition or change. Notwithstanding any other provision of law prescribing limitations, any tax imposed under § 58.1-931 may be assessed until the expiration of three years from the date of such notification.