Yes, but Berkshire’s stock transfer agent won’t handle the conversion from B to A. You sell them on the market and are taxed accordingly.

Their stock transfer agent will give you B shares in exchange for an A share, which is not a taxable event. It’s a mechanism to encourage arbitrageurs to keep the prices of the share classes in lockstep.

https://www.berkshirehathaway.com/brkshareholderinfo/compab....