What is it called when you renew a contract?

Renewing a contract goes by several names depending on the mechanism: a renewal (a new term on the same or updated terms), an extension (lengthening the current term without creating a new one — subtle legal difference), auto-renewal or evergreen renewal (automatic continuation unless notice is given), reinstatement (reviving an already-expired agreement), and novation (technically a replacement contract, sometimes with a new party stepping in).

The distinction that matters most in practice is renewal vs. extension: a renewal often resets terms and re-opens negotiation, while an extension typically carries everything forward unchanged. Which one your contract does is written in its renewal clause — worth reading before the date arrives, because the clause also hides the notice window that decides whether you have a say at all.