Click File. Click Manage Rules & Alerts. In the Rules and Alerts dialog box, click the rule that you want to delete, and then click Delete.
Delete a rule - Microsoft Support
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This cmdlet is available in on-premises Exchange and in the cloud-based service. Some parameters and settings may be exclusive to one environment or the other. Use the Remove-InboxRule cmdlet to remove an Inbox rule.
Remove-InboxRule - mailboxes - Microsoft Docs
docs.microsoft.com > en-us > powershell > module > exchange > remove-i...
To change the settings, name, location or behavior of a rule:
1. Click File > Manage Rules & Alerts.
2. Check the box next to the rule that you want to modify.
3. Click Change Rule, click the type of change you want to make, and then complete the steps.
Edit an Outlook rule - Microsoft Support support.microsoft.com > en-us > office > edit-an-outlook-rule-e6b3dffd-e5...
1. In the Rules and Alerts dialog box, click the first rule in the list, hold down the Shift key and click the last rule to select all rules, then you can click Delete button to delete all selected rules.
Clear all Outlook Rulesat once - Microsoft Community
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