The answer depends on the circumstances of your business.
As a Pure Bookkeeping Licensee you have purchased the license to use the intellectual property in your business as you see fit in part or in whole.
In the event that you sell your business you can transfer your license to the new owner.
The new owner would need to agree to and sign a new License Agreement and continue to pay the ongoing Monthly Fee.
The Pure Bookkeeping System in part or in whole remains the intellectual property of Pure Bookkeeping and it is not a tradable commodity in any other way.