Thanks for reaching out. If you need to delete a Service Bus namespace with geo-replication, make sure you follow the right steps. If you can't delete it, it might be because there's still a secondary region. Remove the secondary region first before trying to delete the primary namespace.
To delete a secondary region, click the ellipsis next to it in the Azure portal and select "Delete." Once the secondary region is gone, you should be able to delete the primary namespace.
If you're still having trouble, check for any active connections or dependencies that might be blocking the deletion.
You can check the below referenced documents on the same
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