Do not present cancelled work as current. A replacement client does not automatically mean a different TN employer or a required new application: first compare the employer, duties and terms with the existing arrangement. Have counsel determine what updated evidence or authorization is needed for the actual replacement work.
Rebuild the evidence around the arrangement that actually exists
Each TN case turns on prearranged professional employment with identified terms. The new engaging party has to describe the duties itself, in its own letter, in enough detail for an officer to see the fit with a listed profession. Where the professional works through an employing firm, that firm's letter can cover the new client work, but the duties and period must be accurate.
TN also requires Canadian or Mexican citizenship, not merely Canadian permanent residence, plus prearranged professional work for a U.S. or foreign employer at a U.S. entity. The licence must be a full licence to practise, and the offered duties must still be engineering work. Build a table listing employer or client, dates, title and a one-line duty summary, then total the qualifying periods; anything short of thirty-six months should not be rounded up.