1. Login in SaaS and go to DX APM.
2. Go to settings >> Downloads
3. Download Workstation.
4. Run it, do the login and when the Console popup, click in Workstation tab >> New Management Module Editor or do a CRTL + M.
5. You will see all your Management Modules, select the desired one and expand the node. You will see a section called "Alert Downtime schedule", select the alerts and delete it:
Now you should be able to delete the Management Module.