Persistence Manager - HasChanges

        (1)                 You can get the specific entities by asking for all entities that have a DataRowState of Added, Deleted, or Modified.  For example, you can get all Employees with changes with this one line of code.
                  mEmployees = mPM.GetEntities<Employee>
                      (DataRowState.Added | DataRowState.Deleted | DataRowState.Modified);;
(2)                 You can tell which columns have changed by comparing the CurrentVersion of the object with the OriginalVersion.  Here is how you can get the Current and Original FirstName of an Employee:

                    Employee aEmployee = mEmployees[0];
                    String currentFirstName = (String)aEmployee["FirstName", DataRowVersion.Current];
                    String originalFirstName = (String)aEmployee["FirstName", DataRowVersion.Original];