Do not assume unresolved material facts can be ignored because the employer wants an early start.
Assess the complete arrangement
Appropriate authorization and its terms govern the work. A planned review or signed offer is not permission to begin.
Build a dated review file around the intended start date, current authorization record, employer changes, travel plan, and any I-129 filing evidence. Make a dated sequence covering the offer, planned admission or I-129 route, authorization point, travel, and any proposed first day of work. Its practical purpose is to decide whether the work described at the proposed start is the same work for which permission is being sought, rather than to collect papers with no stated issue. Hypothetical example: an epidemiologist’s offer moves from research analysis to supervising a clinic team two weeks before travel. Compare the revised supervisory tasks with the occupation presented for TN before preserving the original travel and start schedule. First settle the employer and duties that will exist on day one, then align the application route, travel, and work commencement. A recurring problem is letting a planned start date conceal a material change in duties or employer arrangement. TN is limited to a citizen of Canada or Mexico who has prearranged duties in a listed profession and meets that profession's rule. A Canadian can request admission during inspection or preclearance; an employer can also use an I-129 petition with USCIS. Neither procedure authorizes U.S. self-employment. Move the planned start when authorization is not yet effective, and reassess any last-minute change in employer, occupation, or material duties.