Treat it as a planning target while eligibility, evidence, and the applicable process are actually reviewed. Preparation and the government's decision are separate steps, and an anticipated date is not a form of authorization to work.
Identify what still needs to be confirmed
Ask what remains open before the support letter can be finalized, and who is responsible for confirming it. Check the current procedure before booking any travel. If the employer changes, the duties shift, or a different assignment appears, ask for the arrangement to be reassessed rather than assuming the earlier review still applies.
Work backward from unresolved facts, not the employer's preferred first shift. Confirm Canadian or Mexican citizenship, the exact Appendix 2 to Annex 16-A of the USMCA profession, its minimum credential, and a settled employer letter or contract for prearranged professional activity. Canadian citizens may request TN classification at an eligible port of entry or preclearance location, or a prospective employer may file Form I-129 with USCIS, but neither an appointment plan nor completed drafting authorizes employment. Sequence credential retrieval and employer corrections before fixed travel. A recurring mistake is preserving a date after a material duty or employer change; that revision requires a fresh eligibility review, including the self-employment prohibition.
Hypothetical example: a Windsor university librarian is asked to begin a digital-collections assignment after semester-end, yet her contract mentions occasional teaching and leaves the employing campus unclear. She requests a final duty statement, proof of the actual employer, and records matching the professional category before choosing her Canadian application route. When the university moves the project to a separate foundation, she pauses ticket purchases and has the revised arrangement checked instead of relying on the earlier target date.