But when you do this doesnt it send out all the active alerts all over again..
If this is for Advanced Alerts you can clear out triggered alerts. To clear ALL alerts for an alert definition select the definition in the Manage Alerts window and click the clear button. To clear specific alerts look at the alert list in the active alerts view of the system manager and click the 'clear' button on the far right of the alert item.
This is not available for basic alerts.