123.28—Merchandise remaining in or exported to Canada or Mexico.
(a) In-transit status abandoned.
When the in-transit status of merchandise transiting Canada or Mexico is abandoned and the merchandise is entered for consumption or other disposition in Canada or Mexico, the carrier shall send the in-transit seals and manifests to the port where the manifests were first filed with U.S. Customs, or in the case of trucks under subpart E, the port of exit, with an endorsement by the carrier's agent on each manifest showing that the merchandise was so entered. The carriers shall comply with the export control regulations, 15 CFR part 370.
(b) In-transit merchandise exported to Canada or Mexico.
Merchandise to be exported to Canada or Mexico after moving in-transit through a contiguous country shall be treated as exported when it has passed through the last port of exit from the United States. This paragraph shall control whether or not the merchandise to be exported is domestic or foreign and whether or not it is exported with benefit of drawback. The manifest, shipper's export declaration, and the notice of exportation, if any, shall be filed at the last port of exit from the United States.