Section 251.8 - Modification or extension of authorized importation programs(a) A supplemental proposal to modify or extend an authorized SIP must be submitted in electronic format via the ESG, or to an alternative transmission point identified by FDA, for FDA's consideration.(b) FDA's review and authorization of a supplemental proposal to modify or extend an authorized SIP is governed by this part. In reviewing a supplemental proposal, FDA may take into account information learned subsequent to authorization of the SIP.(c) FDA may authorize a supplemental proposal from a SIP Sponsor to add additional Foreign Sellers or additional Importers to an authorized SIP if FDA determines the SIP Sponsor has adequately demonstrated that the SIP has consistently imported eligible prescription drugs in accordance with section 804 of the Federal Food, Drug, and Cosmetic Act and this part. Each supply chain under a SIP must be limited to one manufacturer, one Foreign Seller, and one Importer.(d) If FDA authorizes changes to a SIP, the Importer must submit a new Pre-Import Request in accordance with § 251.5 .(e) A SIP Sponsor must not make any changes or permit any changes to be made to a SIP without first securing FDA's authorization.(f) A SIP Sponsor may request that FDA extend the authorization period of an authorized SIP. Such a request must be submitted at least 90 calendar days before the SIP's authorization period will expire. To be eligible for an extension of the authorized SIP, a SIP must be up to date on all of the information and records-related requirements of section 804 of the Federal Food, Drug, and Cosmetic Act and this part. FDA may extend the authorization period for up to 2 years at a time.