You can also cancel the effect of a SUBSCRIBE statement by using the UNSUBSCRIBE statement:
UNSUBSCRIBE [ PROCEDURE subscriber-handle ]
    [ TO ] { event-name | ALL } [ IN publisher-handle ]

As with the SUBSCRIBE statement, the default is that UNSUBSCRIBE cancels one or more events for the current procedure. Otherwise, you can use the PROCEDURE subscriber-handle phrase. You can unsubscribe a specific event-name or ALL events. If you include the IN publisher-handle phrase, then the event-name subscription or ALL events, as specified, are canceled only in that handle. If you specify ALL events without a publisher-handle, then all the subscriber-handle’s subscriptions are canceled.