How to do sales order pricing based on order date for just one customer?

Currently, all our sales orders get price from Base Price Revisions based on the request date.  The price field is disabled so that customer service cannot manually change the price.  We now have one customer that wants us to price their sales order based on the order date rather than the request date (and keep it the same).  How do we achieve this for just the one customer when customer service can't manually change pricing and the pricing updates based on the request date?