How do I modify the cost basis in Form 8949 (or in any way), if my broker's 1099-B didn't have it correctly? I sold some mutual fund that was acquired in 2006, and the owner of the broker has changed twice since then so they didn't have the correct basis. Now TT imported 1099-B from the broker but I could not modify the basis. In previous years I was able to do that in the "Forms" mode. Thanks!