I understand you are currently receiving maintenance notifications for a VM since you have the Owner role for that VM. You want to continue receiving notifications for that VM even if you no longer have the Owner role. Please let me know if I am understanding correctly.
We have this information from the FAQ:
Q: How do I get notified about planned maintenance?
A: A planned maintenance wave starts by setting a schedule to one or more Azure regions. Soon after, an email notification is sent to the subscription admins, co-admins, owners, and contributors (One email per subscription with all recipients added). Additional channels and recipients for this notification could be configured using Activity Log Alerts. In case you deploy a virtual machine to a region where planned maintenance is already scheduled, you will not receive the notification but rather need to check the maintenance state of the VM.
So if you are still a Contributor for the VM you will receive the notification. If you don't have any of those roles you can monitor Service Health directly, you can also add service health alert if you want to receive notification.
Hope this helps! Let me know if you still need assistance.
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