Before relying on the changed activity as authorized, with attention to the actual facts and procedural stage.
Provide the new duties promptly
Keep the original scope and amendment together. Avoid continuing with an outdated description solely because the first project letter was already prepared.
Work backwards from the date the employer needs someone in place, and allow time for the support letter to be drafted, reviewed and corrected, which is usually the slowest step. A hiring deadline does not establish direct professional support or authorize work, and a generic letter should not substitute for facts the employer has not decided. Create a dated authorization plan showing the earliest document-ready date, requested classification step, admission or petition decision, first paid duty and any later project change. If authorization is needed, its route and timing depend on the actual facts; do not promise the organization a start date until those steps and the effective permission are clear. Work backward from the proposed first day, listing the employer letter, citizenship proof, credential, assignment terms, and intended procedure as readiness gates. Turn the target start date into a sequence of dependencies: settled duties, completed employer letter, credential availability, procedure choice, and travel date. The frequent mistake is booking a handoff and travel before the employer has finalized duties, leaving the applicant to reconcile a changed job at the last moment.