Voiding Items and Orders in Aldelo Express is simple and easy.  
To void an item just swipe left on the item while in the order entry screen, A void button will appear... Its that easy.  

To void an order, just click on the ellipsis (Button with 3 dots) and choose Void...  Its very Simple... 

The Video below shows you exactly how easy this is in the Aldelo Express point of sale in ipad (and now Android)