@Lee Stevens Thanks for posting in our Q&A.
Currently, there is no method to modify MDM Authority in intune portal.
Based on my research, I find that someone change MDM Authority via PowerShell scripts. Please refer to the following link:
https://call4cloud.nl/2021/01/intune-battle-of-the-mdm-authority/
Note: Non-Microsoft link, just for the reference.
Honestly, I haven't experienced it and not sure if it is a recommended approach. So, it is still suggested to try to create an online support ticket to find a method from the backend. Here is the support link:
https://learn.microsoft.com/en-us/mem/get-support
Thanks for your understanding.
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