If the source of an inbound security group rule or destination of an outbound security group rule needs to be changed, you can first delete the security group rule and add a new one.
Security group rules use the whitelist mechanism. After security group rules are deleted, ECS access failures may occur. You must exercise caution when deleting security group rules.
Delete Multiple Security Group Rules at a Time.
You can also select multiple security group rules and click Delete above the security group rule list to delete multiple rules at a time.