if txtBxFromDate.Text = "12/27/2013 12:00:00 AM" then
txtBxFromDate.Text = "12/27/2013 12:00:00 AM";
DateTime dt = DateTime.ParseExact(txtBxFromDate.Text, "dd/MM/yyyy hh:mm:ss tt", null);
txtboxOutput.Text = dt.Tostring("yyyy/MM/dd");
Happy Coding!
:)