It is not possible to legally impose a contract supplement unless both parties fully understand the new conditions and agree to them in writing. All parties who signed the original contract must also sign the amendment; If one or more parties are unavailable, they may designate agents empowered to sign on their behalf. As a simple example, a deceased person can remember this after he has already completed his will, a collection of pieces he owns and wishes to leave to one of his grandchildren. The deceased can easily pass provisions for the asset with a supplement to the will. A supplement to the treaty defines the definitions, sections, clauses and terms that must be amended, and all parties must approve and sign them. The language of a supplement is sometimes difficult, as the law requires all parties to a contract to respect its original language.