As items are added to and removed from an order, POS automatically determines and re-evaluates the best deal arrangement.
Because an item can only be included in one deal at a time, as a new deal becomes available, an item may be removed from its current deal and added to another.
How a particular deal is applied depends on the relevant deal trigger, as well as the deal item selection method. See the Configuring deal triggers to apply deals at POS and Using Best Price Deals topics for details.
Two small popcorns are added to an order, qualifying for a deal that discounts the second popcorn.
A small coke is then added to the order, qualifying for a new coke and popcorn deal. POS calculates that using this deal would give a better discount to the order overall, so one of the popcorns is removed from the first deal and included in the new deal. The remaining popcorn is sold as a standalone item, not part of any deal.
Note: This functionality is only supported by POS, not any other sales channels.