Under normal circumstances, B-Khata cannot be converted to A-Khata. B-Khata was given to the property because the builder wouldn't have followed the rules while constructing the apartment. The Karnataka Government did try to bring Akrama-Sakrama scheme, which would have converted most of the B-Khata properties to A-Khata. But that has been challenged in the court and stayed. Don't fall for it if the seller says you can convert it to A-Khata, if it is was that easy they would have done it themselves.