An interesting question arose:

 "Process Originators need a 'My Requests' worklist that displays unfinished process instances that the user has originated and allows them to 'cancel' if so desired..."

Here is one way to solve this problem using the hblackpearl] Workflow.Management API to issue a GotoActivity() .

Essentially, a list of all unfinished processes originated by UserA will be displayed in an aspx page.
In this code, there is a cancel link provided for each entry.
If the link is clicked on, process instance is interrogated to see if it contains a "Finish" activity
    If it does contain a "Finish" Activity -  GotoActivity("Finish") is issued.
    If it does not contain a "Finish" Activity - a message is displayed to the user explaining this.

This should help get you on your way to understanding how to instantiate the new Workflow.Management interface in addition to providing a way for the originator to cancel their workflow with reasonable elegance.

You will need to reference SourceCode.Workflow.Management in your project and have a div in your aspx page called divMessage...

Again, it will only successfully cancel processes that contain a "Finish" activity.

Create a page called RequestList.aspx and use the following code in the code behind:  don't forget to reference SourceCode.Workflow.Management and SourceCode.HostClientAPI

private string strProcessID = string.Empty;
protected void Page_Load(object sender, EventArgs e)
        {
            //declare a connection to the k2 management interface
            //modify this to include user/pass after port
            SourceCode.Workflow.Management.WorkflowManagementServer BPM = new SourceCode.Workflow.Management.WorkflowManagementServer("localhost",5555);
            BPM.Open();

                //If a process ID is passed, go ahead with GotoActivity command
                if (RequestI"ProcessID"] != null)
                {
                    strProcessID = Requeste"ProcessID"];
                }

                if (strProcessID != String.Empty)
                {
                    int intProcessID = Convert.ToInt32(strProcessID);
                   
                    //Provide status message with details regarding process being cancelled
                    divMessage.InnerHtml = "Process ID:<b>" + strProcessID + "</b>Selected for Cancel<br>";
                    //..
                    //..

                    //list activities check for one containing "Finish"
                    SourceCode.Workflow.Management.Activities Activities = BPM.GetProcActivities(intProcessID);

                    Boolean blFinishFound = false;

                   
                    foreach (SourceCode.Workflow.Management.Activity Activity in Activities) {
                       
                        if (Activity.Name == "Finish" && blFinishFound == false)
                        {
                            blFinishFound = true;
                           
                            BPM.GotoActivity(intProcessID, "Finish");
                            divMessage.InnerHtml = divMessage.InnerHtml + "Process cancelled successfully<br>";
                        }
                    }   
                    if (blFinishFound == false){
                        divMessage.InnerHtml = divMessage.InnerHtml + "No Finish Activity is available in the process - it cannot be cancelled via this method<br>";
                    }
                }
                //If no Process ID is passed, provide list of processes originated by the current user
                else
                {
                    //format the current user into a string for filtering the process they originated
                    string strFormattedCurrentUser = Convert.ToString("K2:" + HttpContext.Current.User.Identity.Name.ToString());

                    //Snag the process instance list
                    string strblank = string.Empty;
                    SourceCode.Workflow.Management.ProcessInstances processCollection = BPM.GetProcessInstancesAll(strblank, strblank, strFormattedCurrentUser);

                    //look for processes originated by the current user and not yet finished
                    foreach (SourceCode.Workflow.Management.ProcessInstance k2process in processCollection)
                    {
                       

                       
                            divMessage.InnerHtml = divMessage.InnerHtml + "<a href=requestlist.aspx?ProcessID=" + k2process.ID.ToString() + ">Cancel</a> ";
                            divMessage.InnerHtml = divMessage.InnerHtml + "<b>ID: </b>" + k2process.ID.ToString() + " | ";
                            divMessage.InnerHtml = divMessage.InnerHtml + "<b>Status: </b>" + k2process.Status.ToString() + " | ";
                            divMessage.InnerHtml = divMessage.InnerHtml + "<b>Folio: </b>" + k2process.Folio.ToString() + " | ";
                            divMessage.InnerHtml = divMessage.InnerHtml + "<b>Originator: </b>" + k2process.Originator.ToString() + " | <br>";
                       
                    }
                }
                BPM.Connection.Close();
         
       }