Amendment vs. Addendum Amendment changes existing contract terms. Addendum adds new terms without changing original. Both require agreement from all parties. Requirements for Valid Modification All parties must agree to changes Consideration generally required (something new exchanged) Should be in writing (even if original wasn't) Reference the original contract Be signed by all parties Novation Replaces entire original contract with new one. Useful for major changes or replacing a party. Original contract ceases to exist. Best Practices Number amendments sequentially, keep with original contract, require signatures, and summarize all changes clearly.