21 CFR §1315.37

Any manufacturer assigned a procurement quota for a chemical pursuant to § 1315.23 may at any time abandon his right to manufacture all or any part of such quota by filing a notice of such abandonment with the UN Reporting and Quota Section, Diversion Control Division, Drug Enforcement Administration in the online Quota Management System. The Administrator may, in his discretion, allocate the amount among the other manufacturers in proportion to their respective quotas.