Powershell can't reset disk

I'm building servers with disks pre-formatted. I want to use Powershell to reset the disks so they can be used in the primordial pool and be eligible for Storage Spaces. In the Storage Spaces UI, I just click reset and it changes the Partition from MBR to Unknown. That works fine, now I try to do the same with Powershell...

Get-Disk --> shows the partition style is MBR

Get-PhysicalDisk | ft FriendlyName,CanPool --> shows CanPool = False

Reset-PhysicalDisk physicaldisk1 --> has no effect!

Initialize-Disk 1 --> error "the disk is already initialized"

Remote-Partition 1 --> prompts endlessly for partitionnumber, there is only 1 partition

I appreciate any tips.