How to reset the password of the Service Principal created for the System Managed Identity in Azure?

Question

I created an Azure Container Registry with the System Managed Identity. I know how to examine the Service Principal created for it:

C:\> az ad sp show --id 4***8
{
  "accountEnabled": "True",
  "alternativeNames": [
    "isExplicit=False",
    "/subscriptions/d***8/resourcegroups/VictorTestRG/providers/Microsoft.ContainerRegistry/registries/victorTestContainerRegistry"
  ],
  "appId": "7***6",
  "displayName": "victorTestContainerRegistry",
  "keyCredentials": [...],
  "objectId": "4***8",
  "objectType": "ServicePrincipal",
  "odata.metadata": "https://graph.windows.net/2***b/$metadata#directoryObjects/@Element",
  "odata.type": "Microsoft.DirectoryServices.ServicePrincipal",
  "servicePrincipalNames": [
    "7***6",
    "https://identity.azure.net/o***F/p***="
  ],
  "servicePrincipalType": "ManagedIdentity"
}

(I scrubbed certain values and omitted the fields having null or [] as their value for brevity)

Now I would like to reset the credentials for this Service Principal, but none of following worked for me:

C:\> az ad sp credential reset --name 4***8
Resource '4***8' does not exist or one of its queried reference-property objects are not present.
C:\> az ad sp credential reset --name "7***6"
Resource '7***6' does not exist or one of its queried reference-property objects are not present.
C:\> az ad sp credential reset --name victorTestContainerRegistry
Resource '7***6' does not exist or one of its queried reference-property objects are not present.
C:\> az ad sp credential reset --name "https://identity.azure.net/o***F/p***="
Resource '7***6' does not exist or one of its queried reference-property objects are not present.
C:\>

So, how can one reset the credentials of a System Managed Identity?

Answer 1

As Thomas commented, you do not manage the credentials. The point of using a Managed Identity is to get rid of that management.

The system will automatically rotate the certificates used by the identity behind the scenes. You should not need to do anything about it.