The Line Item Detail - List Price field displays the List Price from the item's Inventory database record.
Editing the List Price on the Line Item Detail screen changes the List Price for the current line item only. It also changes the List Price Discount to the right of the List Price field and the List Price Percent Discount to the right of the List Price Discount field. It does not change the List Price field in the item's Inventory database record.
See:
Line Item Detail Screen Contents
Sales Manager Contents