While you are viewing your 
Favorite Items list (in Point of Sale or Item Lookup), tap the Edit button.
Tap the 
control for the item you want to move and drag the item to its new position.
Follow these steps to rearrange the order of the items in your favorites list:
While you are viewing your Favorite Items list (in Point of Sale or Item Lookup), tap the Edit button.
Tap the control for the item you want to move and drag the item to its new position.
Repeat this step for each item you want to reposition.
Tap Done to save your changes.
If you are using an iPad, the item buttons on the Favorites tab of the Point of Sale screen appear in the new order you have defined.
