public void ChangeVMSizes(string newVMSize)
{
var rootElement = XDocument.Load(PartStream.Stream);
foreach (var element in rootElement.Elements().Elements())
element.SetAttributeValue("vmsize", newVMSize);
PartStream.Stream.Position = 0;
rootElement.Save(PartStream.Stream);
PartStream.Stream.SetLength(PartStream.Stream.Position);
Manifest.SetHash(PartStream.Rel.TargetUri, PartStream.ComputeHash());
}