I think you should be able to unmount (remove from Namespace) the volume while the Share is still active.
This way, it would (should) become inaccessible if this is what you want.
Then just remount it again (same Namespace as before, where the share points to) and it will be available again.
This way, you don't have to "stop sharing" aka. delete the share and recreate it afterwards, saves some work!
Please test with a test-volume/share first!
