We are unable to manually clear active alerts from Coal Solarwinds – specifically “STANDARD: Node rebooted” alerts as these cause some noise on the Active Alerts page.
help here how to proceed
First of all, are the nodes really rebooted? If yes then this is per se a correct Info you are receiving. If you don't want to be alerted when a Node reboots, go to the alerts page, manage alerts and switch off the Alert for "node rebooted".
If you only want to be alerted when certain Nodes are rebooted think about implementing a custom node Property (e.g. CP_Node_Reboot_Alert) and use this as an additional check in the alert condition.