public KnowledgeGraphRelationshipDescription( 
   Guid origin,
   Guid destination,
   IReadOnlyDictionary<string,object> attributes
)

var create_rel2 = await QueuedTask.Run(() =>
{
  //Instantiate an operation for the Create
  var edit_op = new EditOperation()
  {
    Name = "Create a new relationship record",
    SelectNewFeatures = true
  };

  //Use datasets or feature layer(s) or standalone table(s)
  //Get a reference to the KnowledgeGraph
  //var kg = ... ; 

  //We will use a relate called 'HasEmployee' to relate an Organization w/ a Person
  //Use either tables or map members to get the rows to be related...
  var org_fc = kg.OpenDataset<FeatureClass>("Organization");
  var person_tbl = kg.OpenDataset<Table>("Person");

  //Get the relationship dataset
  //We can use either a table or standalone table
  var emp_tbl = kg.OpenDataset<Table>("HasEmployee");

  // get the origin, destination records
  Guid guidOrigin = Guid.Empty;
  Guid guidDestination = Guid.Empty;
  using (var rc = org_fc.Search())
  {
    if (rc.MoveNext())
      //Use the KnowledgeGraphPropertyInfo to avoid hardcoding...
      guidOrigin = rc.Current.GetGlobalID();
  }
  using (var rc = person_tbl.Search())
  {
    if (rc.MoveNext())
      //Use the KnowledgeGraphPropertyInfo to avoid hardcoding...
      guidDestination = rc.Current.GetGlobalID();
  }

  //Add any extra attribute information for the relation as needed
  var attribs = new Dictionary<string, object>();
  attribs["StartDate"] = new DateTimeOffset(DateTime.Now);

  var rd = new KnowledgeGraphRelationshipDescription(guidOrigin, guidDestination, attribs);
  //Add a create for the relationship to the operation
  edit_op.Create(emp_tbl, rd);

  //Do the create
  return edit_op.Execute();
});

await QueuedTask.Run(() =>
{

  var edit_op = new EditOperation()
  {
    Name = "Delete a Relationship record"
  };

  //We are  going to use mapmembers in this example
  //we could equally use feature classes/tables
  var kg_layer = mv.Map.GetLayersAsFlattenedList()?
                .OfType<ArcGIS.Desktop.Mapping.KnowledgeGraphLayer>().First();

  //entities
  var entityOrg = kg_layer.GetStandaloneTablesAsFlattenedList()
                  .First(child_layer => child_layer.Name == "Organization");
  var entityPerson = kg_layer.GetStandaloneTablesAsFlattenedList()
                  .First(child_layer => child_layer.Name == "Person");

  //Relationship
  var rel_stbl = kg_layer.GetStandaloneTablesAsFlattenedList()
                  .First(child_layer => child_layer.Name == "HasEmployee");

  // get the origin, destination records
  Guid guidOrigin = Guid.Empty;
  Guid guidDestination = Guid.Empty;
  using (var rc = entityOrg.Search())
  {
    if (rc.MoveNext())
      //Use the KnowledgeGraphPropertyInfo to avoid hardcoding...
      guidOrigin = rc.Current.GetGlobalID();
  }
  using (var rc = entityPerson.Search())
  {
    if (rc.MoveNext())
      //Use the KnowledgeGraphPropertyInfo to avoid hardcoding...
      guidDestination = rc.Current.GetGlobalID();
  }

  var rd = new KnowledgeGraphRelationshipDescription(guidOrigin, guidDestination);
  edit_op.Delete(rel_stbl, rd);
  edit_op.Execute();//Do the delete
});