Explain material terms accurately, including what work the applicant is actually engaged to perform.
Make the proposed stages understandable
Identify whether the assessment affects duties, continued employment or another actual condition. Do not suppress a term that materially changes the assignment or describe an unsettled offer as unconditional.
Build the support letter from the signed offer, assessment policy, and assignment plan, checking that dates, pay, duties, supervision, and the condition’s consequences agree across all records. It should identify the USMCA-listed profession, explain the prearranged work, and state whether any productive duties occur before the assessment. Canadian or Mexican citizenship and that profession’s prescribed qualification remain necessary; Canadian residence status alone does not qualify. The applicant must not present work for a U.S. business that she owns or controls as TN employment. For a Canadian, port-of-entry processing or an employer-filed I-129 may be considered on the facts. A frequent mistake is deleting the condition from the letter while leaving it in the offer, creating an avoidable credibility problem.
Hypothetical example: A forestry consultant from Saint-Charles-de-Bourget is engaged only if she completes a field-method review after arrival. Her employer’s letter states what consulting services begin upon admission, when the review occurs, and what happens if she does not pass. She brings the underlying conditional offer and proof meeting the profession’s requirements, rather than asking the employer to call the position unconditional. That consistent record lets the reviewing officer assess the real engagement instead of discovering a different arrangement in later documents.