In Azure Monitor, alert rules use action groups to define who receives notifications (emails, SMS, push notifications, webhooks, etc.) when an alert is triggered.
If you are currently receiving 100+ email alerts for failed sign-ins daily, and you want a new administrator to receive them instead, the correct way is to modify the action group and update or replace the email recipient .
According to Microsoft Learn ( "Cr eate and manage action groups in Azure Monitor" ):
"Action groups specify the recipients of alerts. You can update an existing action group to add, remove, or modify the recipients for email, SMS, push, or ITSM connections." Thus, modifying the action group directly changes who receives the alerts.