Add-AzureRmAccount
$currentAzureContext = Get-AzureRmContext
$tokenCache = $currentAzureContext.TokenCache
$refreshToken = $tokenCache.ReadItems().RefreshToken
$tenantid = $currentAzureContext.Tenant.Id

$body = "grant_type=refresh_token&refresh_token=$($refreshToken)&resource=74658136-14ec-4630-ad9b-26e160ff0fc6"
$tokresponse = Invoke-RestMethod "https://login.windows.net/$tenantid/oauth2/token" -Method POST -Body $body -ContentType 'application/x-www-form-urlencoded'

$headers = @{"Authorization" = "Bearer $($tokresponse.access_token)"}
$objid = "<UserAccountObjId>"
$response = Invoke-RestMethod "https://main.iam.ad.ext.azure.com/api/UserDetails/$objid" -Headers $headers -Method GET