Price Effective Date Field


I went into a sales order to see if I manually change a price effective date on the order if that date would stick. The price effective date reverted back to match the request date.
I know if you change a price manually in a sales order field that price would stand. Why doesn't the price effective date field work the same way? Is it possible to override a price effective date on an order? I thought maybe someone in my company may have access/ability to change it. Thank you for your help.