If you have links from a bracket to bracket or round-robin to bracket and want to delete all the links:
Go to Menu > Manage > Brackets/Round-Robins > Brackets.
Select the bracket you want to unlink.
Click on Display more options (top right)
Click on Delete links.
If you want to delete a few links only,
Go to Menu > Manage > Brackets/Round-Robins > Bracket linker.
Find your bracket on the left.
The linked bracket on the right.
Select the delete.
Click on Delete link button in the middle.