The Delete (Sort Block) command, accessed on the right-click context menu, deletes the selected sort block from the project. You will be prompted to confirm the deletion before the sort block is removed.
Since sort blocks are defined per-project, this means that no other project team members will have access to this sort block for the selected project. However, deleting a sort block from one project will not affect any other project.
Sort blocks marked as essential are internally referenced by GENESYS and key to its proper operation, even if the particular sort block is not one that you choose to use. Essential sort blocks cannot be deleted. If you attempt to do so, you will notified that the sort block is essential, and it will not be removed from the project.