But from a practical standpoint how do you sell 'a branch' of a software-based company? Do you sell/license the software? Do you charge this new company for AP

But from a practical standpoint how do you sell 'a branch' of a software-based company? Do you sell/license the software? Do you charge this new company for API access to the 'old' services? I've had a really hard time trying to imagine how this could play out in fair agreement. I think the only real option is to exit the market.