There are three snapshot settings that you can modify: the frequency of snapshots, how many are retained on the database servers, and whether to copy new snapshots to the management server. When the database is stopped, you can change any of these settings. If the database is running, you can only change whether the snapshots are copied to the management server or not.
To modify the snapshot settings, click Edit on the Snapshots panel. The changes you make on the Edit Snapshots dialog go into effect as soon as you click OK. So, if the database is running, changes to the copying of snapshots to the management server are communicated the the cluster nodes immediately. If the database is not currently running, all changes go into effect the next time the database starts.