Modify panel > Make a patch selection. > Modifier List > Delete Patch
Make a selection. > Modifiers menu > Patch/Spline Editing > Delete
Delete Patch provides parametric deletion based on the current sub-object level in the stack. The possible choices are vertices, edges, patches, and elements. Apply the Delete Patch modifier to delete the geometry specified at that sub-object level.
For example, you can apply a Patch Select modifier, select a row of patches in a patch sphere, and then apply a Delete Patch modifier to delete those patches. To undo the deletion, remove the Delete Patch modifier.
Example: To delete a patch in a sphere: