39 CFR §3040.180

1. (a)Whenever the Postal Service proposes material changes to a product description in the Mail Classification Schedule, no later than 30 days prior to implementing the proposed changes, it shall submit to the Commission a request to change the product description in the Mail Classification Schedule.
2. (b)The request shall:
   1. (1)Include a copy of the applicable sections of the Mail Classification Schedule and the proposed changes therein in legislative format; and
   2. (2)Provide all supporting justification for the changes upon which the Postal Service proposes to rely.