The Sales Re-ordering functionality acts as an upselling tool for businesses, granting them the visibility of previous Sales history right from the "Sales Order". 

From the "Sales Order" card, you can now access a "Sales Item Reorder" list which will show you all items they have either previously purchased or "Item Inclusion" (items you have stored in Business Central that you want to promote to Customers). If the Customer tells you they don't like an item, you can remove this off the re-order list permanently in 1 click. 

What's more, as you highlight the lines, the Item information is displayed in the Factbox, showing you the actual inventory you have available, so you can see what's available, advise the Customer what they previously purchased and add on their order Qty directly onto the line. Once you've confirmed all the items and qtys the Customer wants to include, closing the screen will immediately add these items as lines onto the Sales Order, making the whole ordering process smoother, quicker and improved. 

Check out the following articles for more information on how to use this feature.