public/Remove-EntraIdGroupOwner.ps1

<#!
.SYNOPSIS
    Removes owners from an Entra ID (Azure AD) group by group Id or display name.

.DESCRIPTION
    This function removes specified owners from an Entra ID group using Microsoft Graph. It supports searching for the group by Id or display name. Owners can be users, identified by their UPN.

.PARAMETER GroupId
    The object Id (GUID) of the Entra ID group to remove owners from.

.PARAMETER GroupDisplayName
    The display name of the Entra ID group to remove owners from.

.PARAMETER Owners
    An array of user principal names (UPNs) to remove as owners.

.EXAMPLE
    Remove-EntraIdGroupOwner -GroupId "00000000-0000-0000-0000-000000000001" -Owners @("user1@contoso.com", "user2@contoso.com")
    Removes the specified users as owners from the group with the specified Id.

.EXAMPLE
    Remove-EntraIdGroupOwner -GroupDisplayName "My Security Group" -Owners @("user1@contoso.com", "user2@contoso.com")
    Removes the specified users as owners from the group with the specified display name.

.NOTES
    This function requires Microsoft Graph PowerShell SDK to be installed and authenticated.
#>

function Remove-EntraIdGroupOwner {
    [CmdletBinding(DefaultParameterSetName='ById', SupportsShouldProcess = $true)]
    param(
        [Parameter(Mandatory, ParameterSetName='ById', Position=0, ValueFromPipeline, ValueFromPipelineByPropertyName)]
        [string]$GroupId,
        [Parameter(Mandatory, ParameterSetName='ByDisplayName', Position=0, ValueFromPipeline, ValueFromPipelineByPropertyName)]
        [string]$GroupDisplayName,
        [Parameter(Mandatory)]
        [array]$Owners
    )

    process {
        if ($PSCmdlet.ShouldProcess("Group: $GroupDisplayName ($GroupId)", "Remove specified owners")) {
            Test-GraphAuth

            # Resolve group Id or group display name based on parameter set
            switch ($PSCmdlet.ParameterSetName) {
                'ByDisplayName' {
                    $groupParams = @{
                        DisplayName = "$GroupDisplayName"
                    }
                    $group = Get-EntraIdGroup @groupParams
                    if (!$group) {
                        Write-Warning "No group found with display name '$GroupDisplayName'."
                        return
                    }
                    $GroupId = $group.Id
                }
                'ById' {
                    $groupParams = @{
                        Id = $GroupId
                    }
                    $group = Get-EntraIdGroup @groupParams
                    if (!$group) {
                        Write-Warning "No group found with Id '$GroupId'."
                        return
                    }
                    $GroupDisplayName = $group.DisplayName
                }
            }

            # Remove all provided owners directly
            foreach ($ownerEntry in $Owners) {
                if ($ownerEntry -like '*@*') {
                    # User
                    $ownerUserObj = Get-EntraIdUser -UserPrincipalName $ownerEntry
                    if ($null -ne $ownerUserObj) {
                        try {
                            $ownerUserId = $ownerUserObj.Id
                            $removeParams = @{
                                GroupId = $GroupId
                                DirectoryObjectId = $ownerUserId
                            }
                            Remove-MgGroupOwnerDirectoryObjectByRef @removeParams
                            Write-Output "Removed Owner (user) $ownerEntry from group $GroupDisplayName ($GroupId)."
                        } catch {
                            Write-Warning "Failed to remove Owner (user) $ownerEntry from group $GroupDisplayName ($GroupId): $($_.Exception.Message)"
                        }
                    } else {
                        Write-Warning "User not found: $ownerEntry"
                    }
                } else {
                    # Group
                    $ownerGroupObj = Get-EntraIdGroup -DisplayName $ownerEntry
                    if ($null -ne $ownerGroupObj) {
                        try {
                            $ownerGroupId = $ownerGroupObj.Id
                            $removeParams = @{
                                GroupId = $GroupId
                                DirectoryObjectId = $ownerGroupId
                            }
                            Remove-MgGroupOwnerDirectoryObjectByRef @removeParams
                            Write-Output "Removed Owner (group) $ownerEntry from group $GroupDisplayName ($GroupId)."
                        } catch {
                            Write-Warning "Failed to remove Owner (group) $ownerEntry from group $GroupDisplayName ($GroupId): $($_.Exception.Message)"
                        }
                    } else {
                        # Try as service principal
                        $ownerSpnObj = Get-EntraIdServicePrincipal -DisplayName $ownerEntry
                        if ($null -ne $ownerSpnObj) {
                            try {
                                $ownerSpnId = $ownerSpnObj.Id
                                $removeParams = @{
                                    GroupId = $GroupId
                                    DirectoryObjectId = $ownerSpnId
                                }
                                Remove-MgGroupOwnerDirectoryObjectByRef @removeParams
                                Write-Output "Removed Owner (service principal) $ownerEntry from group $GroupDisplayName ($GroupId)."
                            } catch {
                                Write-Warning "Failed to remove Owner (service principal) $ownerEntry from group $GroupDisplayName ($GroupId): $($_.Exception.Message)"
                            }
                        } else {
                            Write-Warning "Group or ServicePrincipal not found: $ownerEntry"
                        }
                    }
                }
            }
        }
    }
}