Hello Christopher,

Thank you for logging this feature request. We will monitor the community interest in such a feature and consider it for implementation in a future release.

Currently, if this functionality is mandatory for you I can suggest obtaining the options of the DropDownList/Compobox, updating the cascadeFrom to the desired parent and destroying and re-initializing the component with the new options:

function changeParent(){
    var ddl = $("#child").getKendoDropDownList();
    var options = ddl.options;
    options.cascadeFrom = "parent2";
    ddl.destroy();
    $("#child").kendoDropDownList(options);
  }

Regards,
Aleksandar
Progress Telerik