State what is actually committed and what remains conditional.
Read the clause precisely
Identify who can exercise the option and whether that has occurred. A hoped-for continuation should not be converted into an unqualified employer commitment in the support letter.
A TN professional is admitted for a period matching the employment, up to three years, and may seek further periods as long as the work remains prearranged professional employment in the listed occupation and the applicant's intent remains temporary. The state board's licence is a condition of practising veterinary medicine in that state, and the employer, not the immigration officer, is responsible for not assigning clinical work until it exists. Engineer exists on the list for engineering practice, and is met by a baccalaureate or licenciatura degree or by a state or provincial licence; an officer who reads that entry will apply what it means rather than what it was hoped to mean. The practical consequence is that the offered position must be described as it will actually be performed in the interval, most often as professional survey work carried out under the responsibility of a licensed surveyor. Two further conditions apply regardless of which profession is chosen: the employment must be prearranged with a United States employer or entity, and the applicant must be a citizen of Canada or Mexico.