File after the US role is restructured on paper and the foreign-year and reporting-line evidence is reconciled, and allow for standard processing or premium processing before the intended start; the manager cannot begin managing the US plant until the petition is approved and she is admitted in L-1 status. Do not let a seasonal production start dictate a premature filing.
Sequence restructuring, filing and admission
A practical order: first, confirm the continuous foreign year and note any leaves; second, define the US function-manager role, its reporting line and its budget, and have the US plant adopt that structure formally; third, gather the affiliate evidence and the operational records; fourth, file Form I-129 with the L supplement, choosing premium processing if the production calendar demands a fast answer; fifth, once approved, the manager, as a Canadian citizen, presents the approval notice at a port of entry for admission in L-1 status without a visa stamp. Interim visits to the US plant to observe an audit or attend a meeting are visitor activities and should not shade into running the program before admission. Initial L-1A approval is ordinarily up to three years for an established affiliate, with extensions to a maximum of seven years; track the total from the first admission.