H Madan,
Yes youare right about the report tab usage.
Mitigation monitor is sole responsible yo keep checking whether or not the mitigation is being performed. This monitoring can be done either manually or by scheduling the alert generation.
Reports which are maintained in reports tab of mitigating control, will trigger an e-mail to the Mitigation approver if control monitor does not run that report with in the frequency mentioned.
Alerts can be set through the program mentioned below by executing the Tcode GRAC_ALERT_GENERATE.
You can refer to:
Creation of Mitigation Controls in GRC 10.0
And these reports are standard ones.
Let us know for any more concerns.
Regards,
Ameet