public bool ChangeMachineDetails(Credentials c, MachineContents newM,
				MachineContents oldM)
        {
            var cl = new Ref.FileSyncModelClient();
            try {
                if (c == null)
                    throw new ArgumentNullException("c", "user credentials must be provided");
                if (newM == null)
                    throw new ArgumentNullException("newM", "new machine identity must be provided");
                if (oldM == null)
                    throw new ArgumentNullException("oldM", "old machine identity must be provided");

                bool result = false;
                result = cl.ChangeMachineDetails(c, newM, oldM);
                cl.Close();
                return result;
            } catch (Exception ex) {
                cl.Abort();
                throw new ActionException("Error while updating machine details.",
                    ActionType.Machine, MemeType.Fuuuuu, ex);
            }
        }