19 C.F.R. § 122.94
(b) Clearance not at place of final departure. If an aircraft is cleared at a place other than the place of final departure from the U.S., the aircraft commander or its authorized agent shall:
(2) Submit to the Customs officer in charge the certificate received at the place the merchandise was taken on board. The clearance certificate is kept by the Customs officer in charge until departure.
This procedure shall be followed at each place of landing before final departure.
[T.D. 88-12, 53 FR 9292, Mar. 22, 1988; T.D. 00-22, 65 FR 15618, Mar. 29, 2000]