My two siblings and I inherited an unimproved lot in 2000 and established ownership as tenants in common. In 2007, one of my siblings died and her 1/3 share was left to my brother and I, equally. Can we get an updated cost basis that is based on the value of her 1/3 share at the time of her death? I assume that the updated basis of her 1/3 share would have to be averaged with the value of our 1/3 shares in the year 2000.