7 CFR §789.16

1. (a)The priority rating on a rated order may be changed or canceled by:
   1. (1)An official action of USDA; or
   2. (2)Written notification from the person who placed the rated order.
2. (b)If an unrated order is amended so as to make it a rated order, or a DO rating is changed to a DX rating, the supplier must give the appropriate preferential treatment to the order as of the date the change is received by the supplier.
3. (c)An amendment to a rated order that significantly alters a supplier's original production or delivery schedule constitutes a new rated order as of the date of its receipt. The supplier must accept or reject the amended order according to the provisions of § 789.13.
4. (d)The following amendments do not constitute a new rated order:
   1. (1)A change in shipping destination;
   2. (2)A reduction in the total amount of the order;
   3. (3)An increase in the total amount of the order that has a negligible impact upon deliveries;
   4. (4)A minor variation in size or design; or
   5. (5)A change that is agreed upon between the supplier and the customer.
5. (e)If a person no longer needs items or services to fill a rated order, any rated orders placed with suppliers for the items or services, or the priority rating on those orders, must be canceled.
6. (f)When a priority rating is added to an unrated order, or is changed or canceled, all suppliers must be promptly notified in writing.