19 C.F.R. § 142.44
After an application for Line Release has received final approval, filers must provide the port director, in writing, with a range of entry numbers for use in the system so that an entry number can be assigned automatically to each Line Release transaction. For the purposes of this subpart, "entry number", when the release is an immediate delivery, merely refers to the Line Release transaction number; this number does not become the actual entry number until an entry for the merchandise released under the immediate delivery procedure is filed. A separate range must be provided for each Line Release site at the port. These entry numbers shall be used for assignment within the Line Release system. Entry filers shall not assign these numbers to other entry transactions.
19 C.F.R. § 142.44