NtManagePartition - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTMMAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)
#if (PHNT_VERSION >= PHNT_THRESHOLD)

NTSYSCALLAPI
NTSTATUS
NTAPI
NtManagePartition(
    _In_ HANDLE TargetHandle,
    _In_opt_ HANDLE SourceHandle,
    _In_ PARTITION_INFORMATION_CLASS PartitionInformationClass,
    _Inout_updates_bytes_(PartitionInformationLength) PVOID PartitionInformation,
    _In_ ULONG PartitionInformationLength
    );

#endif
#endif
#endif

View code on GitHub
#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwManagePartition(
    _In_ HANDLE TargetHandle,
    _In_opt_ HANDLE SourceHandle,
    _In_ PARTITION_INFORMATION_CLASS PartitionInformationClass,
    _Inout_updates_bytes_(PartitionInformationLength) PVOID PartitionInformation,
    _In_ ULONG PartitionInformationLength
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit.