49 CFR 1305.4 - Notice requirement.
(a) A pipeline carrier may not increase any rates or charges, or change any service terms (except for changes that are equivalent to rate reductions) unless 20 days have expired after written or electronic notice has been provided to all persons who, within the previous 12 months:
(2) Have made arrangements with the carrier for a shipment that would be subject to the increased rates or changed service terms.
(b) The notice required by this section may be provided either in writing or in electronic form, as agreed to by the parties. If the parties cannot agree, the information is to be provided in electronic form where both parties have the requisite capabilities; otherwise, it is to be provided in writing.
(c) For purposes of this section, a mailed notice is deemed “provided” on the date such notice is postmarked.
(d) The notice required by this section must clearly identify the increase in rates or charges or the change in service terms.