How do I clean the drain pump when it is blocked?

Switch off the appliance and unplug it, then open the service flap and remove the drain hose from its retainer to pour out the water into a suitable container. Carefully unscrew the pump cover, clean the interior, pump cover thread, and pump housing, ensuring the impeller can rotate freely, then refit and screw on the pump cover with the handle in a vertical position. After cleaning, pour 1 litre of water into dispenser II and run the Rinse/Spin/Drain programme to prevent unused detergent from going directly into the drain. (Page 44-45)