The same way any other company would: dated employment records, ownership and control documents, and a clear account of duties before and after the transfer, distinct from any informal family understanding of who runs things.
Formalize what has been informal
Gather genuine existing share registers, resolutions and employment records. If current authority is newly delegated, date that decision accurately; do not manufacture historical records. Label retrospective explanations as such and support them with available contemporary evidence. Identify which decisions remain with other relatives so the proposed transferee’s authority is not overstated.
Create four linked evidence groups: ownership and control between entities, continuous foreign employment, the applicant's former duties, and the proposed U.S. authority. Useful records can include formation papers, share ledgers, payroll history, organization charts, budgets, approvals, and examples of decisions actually made. For an established U.S. operation, the organization must do business in America and another country throughout the stay, so gather operating evidence from both sides. The recurring mistake in a closely held company is backdating a resolution to make informal authority appear historical. Instead, identify when powers changed, distinguish contemporary records from later explanations, and reconcile names or percentages across every corporate document.
Hypothetical example: A greenhouse-supplies wholesaler near Strathroy-Caradoc formalizes a transfer after years of verbal family decisions. Its finance director collects dated purchase approvals, staff reviews, bank mandates, and genuine ownership records, then explains a recent delegation in a current resolution. She does not rewrite old minutes. The resulting chronology shows which management powers existed during the qualifying foreign employment and which begin only with the planned U.S. assignment.