A commercial agreement is not itself an immigration extension. Review the applicable process and current status.
Track separate dates
Keep the contract end date and authorized stay distinct. Do not continue work based only on a signed renewal when the required permission has not been established.
Set a milestone for receiving the second employer's complete duty letter, a separate milestone for the compatibility review against the first role, and a final milestone for confirming authorization before work starts. Allow extra time compared with a straightforward single-employer case, since the structural review itself takes real work before any filing timeline starts. Set a date for the employer to deliver a revised duty description if needed, and a separate date for confirming licence or registration status. A first review should create a dated sequence from the signed offer through the chosen admission or petition step, travel, and the first lawful workday. TN preparation and the government's decision are separate steps, and an expected start date is not itself authorization to begin work. The immigration step can often be completed relatively quickly once the qualification documents and the employer's letter exist, and it should be scheduled behind the licence.