using System.Diagnostics;

public void CloseProccessOfAnotherApplication(string name)
        {
            
                if (string.IsNullOrWhiteSpace(name))
                {
                    iap.WriteLog("Process Name Was Null! Error. Please Pass A Process Name");
                    Environment.Exit(1);
                }
                Process[] mainAppProcessOrProcessesRunning = Process.GetProcessesByName(name);
                foreach(var p in mainAppProcessOrProcessesRunning)
                 {
                p.Kill();
                // or p.close(); 
                /*If you have permission issues then you have to capture each MainWindow using the proccess, focus that window, and do mainWindow.Exit(). 
                This may require using system32 automation to mimic the user. You may also have to pull each Modal attached to the main window and close those before hand.*/
              
                 }
            
        }