Use it as a planning target while the underlying eligibility and evidence are reviewed, not as a scheduling commitment. TN preparation, any USCIS petition process, and the final admission decision are separate steps, and a requested date does not authorize work in advance of them.
Identify what has to be confirmed before travel
Ask which facts remain outstanding and who must confirm them before arranging travel. Check the selected crossing’s current procedures; general operating hours do not guarantee an immediate TN decision. A new employer, revised duties or different assignment should prompt review of the actual change rather than reliance on the old plan.
A port-of-entry application can be decided the same day, but assembling a licence confirmation, translations and a correct letter typically takes several weeks, and an I-129 petition adds USCIS processing time.
Where the employer needs cover in the interim, that is a staffing question to be solved separately rather than a reason to compress the immigration one, and saying so early usually produces a better conversation than discovering it after a second attempt.