Retain the old price in the sales order even after new price is updated

Summary:

Hi, we are using customer specific price list and in that we are using Tier based price list , like for this quantity ranges, a price is applicable.

The scenario is a sales order has been raised for a particular quantity, so a price say 10 dollars has been selected in that sales order. after two days that price has been updated to a new value in the price list say 15 dollars. Now in that sales order raised before, after a revision, new price is reflected which is 15 dollars.

Is there a way to stop the old sales order to reflect new updated price and continue with the old 10 dollar price??